TR1074 vSphere MEM

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Technical Report

Configuring and Installing the EqualLogicMultipathing Extension Module for VMwarevSphere and PS Series SANsAbstract

This Technical Report will explain the benefits ofthe EqualLogic Multipathing Extension Module(MEM) for VMware vSphere 5.x and 4.1 whichprovides multipath I/O for highly available accessto the Dell EqualLogic PS Series SAN

TR1074

V1.3


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Copyright 2013 Dell Inc. All Rights Reserved.

EqualLogic is a registered trademark of Dell Inc.

Dell is a trademark of Dell Inc.

All trademarks and registered trademarks mentioned herein are the property of their respectiveowners.

Information in this document is subject to change without notice.

Dell Inc. will not be held liable for technical or editorial errors or omissions contained herein. Theinformation in this document is subject to change.

Reproduction in any manner whatsoever without the written permission of Dell is strictly

prohibited.

Authored by: David Glynn

[September 2013]

WWW.DELL.COM/PSseries
http://www.dell.com/PSserieshttp://www.dell.com/PSserieshttp://www.dell.com/PSseries


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Preface

PS Series arrays optimize resources by automating performance and network load balancing. Additionally,PS Series arrays offer all-inclusive array management software, host software, and free firmware updates.

Audience

The information in this guide is intended for administrators of VMware vSphere environmentutilizing EqualLogic iSCSI arrays.

Related Documentation

For detailed information about PS Series arrays, groups, volumes, array software, and host software, log in

to theDocumentation pageat the customer support site.

Dell Online Services

You can learn about Dell products and services using this procedure:

1. Visithttp://www.dell.comor the URL specified in any Dell product information.

2. Use the locale menu or click on the link that specifies your country or region.

Dell EqualLogic Storage Solutions

To learn more about Dell EqualLogic products and new releases being planned, visit the DellEqualLogicTechCenter site:http://delltechcenter.com/page/EqualLogic. Here you can also find articles,

demos, online discussions, technical documentation, and more details about the benefits of our productfamily.

For an updated Dell EqualLogic compatibility list please visit the followingURL:https://eqlsupport.dell.com/support/download.aspx?id=6442454231&langtype=1033
https://eqlsupport.dell.com/support/resources.aspx?id=2495https://eqlsupport.dell.com/support/resources.aspx?id=2495https://eqlsupport.dell.com/support/resources.aspx?id=2495http://www.dell.com/http://www.dell.com/http://www.dell.com/http://delltechcenter.com/page/EqualLogichttp://delltechcenter.com/page/EqualLogichttp://delltechcenter.com/page/EqualLogichttps://eqlsupport.dell.com/support/download.aspx?id=6442454231&langtype=1033https://eqlsupport.dell.com/support/download.aspx?id=6442454231&langtype=1033https://eqlsupport.dell.com/support/download.aspx?id=6442454231&langtype=1033https://eqlsupport.dell.com/support/download.aspx?id=6442454231&langtype=1033http://delltechcenter.com/page/EqualLogichttp://www.dell.com/https://eqlsupport.dell.com/support/resources.aspx?id=2495


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Table of Contents

Revision Information ....................................................................................................................................... iiiExecutive Summary .......................................................................................................................................... 1Introduction ......................................................................................................................................................... 1Deploying the EqualLogic MEM .................................................................................................................. 2

Deployment Considerations: Requirements .................................................................... 2Deployment Considerations: Storage Heartbeat on vSphere 5.0 and 4.1 ........ 3Deployment Considerations: iSCSI Connection Count ............................................. 3Deployment Considerations: iSCSI Login Timeout on vSphere 5.x .................... 4Deployment Considerations: Best Practices parameter in MEM 1.2.................... 5

Configuring an iSCSI vSwitch for Multipathing .................................................................................... 6Interactive Mode configuration .............................................................................................. 6Unattended Mode configuration ............................................................................................ 8

Installing the EqualLogic MEM ..................................................................................................................... 9Verification of MEM iSCSI Session Creation ........................................................................................ 10Advanced iSCSI connection configuration parameters ................................................................. 11

Increasing the default values ................................................................................................. 11Decreasing the default values ................................................................................................ 12Setting the EHCM configuration values under vSphere 5.x ................................... 13Setting the EHCM configuration values under vSphere 4.1 ................................... 13

Summary ............................................................................................................................................................. 14Technical Support and Customer Service ............................................................................................14Appendix A: Example iSCSI vSwitch configurations ........................................................................15

Overriding hardware iSCSI offload default utilization ............................................... 15Utilizing a vNetwork Distributed Switch .......................................................................... 15Enabling Jumbo Frames ........................................................................................................... 15Setting the iSCSI discover address....................................................................................... 15

Appendix B: Installing the MEM with VMware Update Manager ................................................ 16


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Revision InformationThe following table describes the release history of this Technical Report.

Report Date Document Revision

1.0 November 2011 Initial Release1.1 February 2012 General Availability updates

1.2 September 2012 Updated Storage Heartbeat recommendation for vSphere 5.1

1.3 September 2013 Updated to reflect firmware 6.0 and vSphere 5.5

The following table shows the software and firmware used for the preparation of this Technical

Report.

Vendor Model Software Revision

VMware vSphere 4.1 or 5.x with Enterprise licensing 4.1 or 5.x

Dell Dell EqualLogic PS Series SAN 4.3 or above

Dell EqualLogic Multipathing Extension Module

for VMware vSphere 5.x

1.2

Dell EqualLogic Multipathing Extension Module

for VMware vSphere 4.1

1.1.1

The following table lists the documents referred to in this Technical Report. All PS Series

Technical Reports are available on the Customer Support site at: support.dell.com

Vendor Document Title

Dell Dell EqualLogic PS Series Array Administration Guide

Dell EqualLogic Multipathing Extension Module: Installation and User Guide

VMware vSphere Storage Guide

VMware vSphere Installation and Setup Guide

VMware Installing and Administering VMware vSphere Update Manager

VMware vSphere Command-Line Interface Concepts and Examples

VMware vSphere Management Assistant Guide

CONVENTIONS

Throughout this document the term ESXi is used to refer to both ESX and ESXi hypervisors. The

EqualLogic MEM is supported on vSphere 4.1 ESX and ESXi, and vSphere 5.x ESXi hypervisor

platforms with Enterprise or Enterprise Plus licensing.


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Executive Summary

High availability is an important requirement of any system in the datacenter. Thisavailability is even more critical if that system is a component in the virtual

infrastructure upon which a virtualized datacenter is built. Redundant hardware and

RAID technologies form a critical foundation. When using shared storage, the pathsfrom the servers to the storage need to also be redundant and highly available.

This Technical Report details the benefits of Dells EqualLogic Multipathing ExtensionModule, MEM, for VMware vSphere, as well the installation and configurationprocess to provide multipath I/O for high available access to the Dell EqualLogic PS

Series SAN. Also covered are a number of overall virtual environment iSCSI designconsiderations and best practices.

Introduction

VMware vSphere offers many enhancements to the software iSCSI initiator beyondbasic iSCSI SAN connectivity. The most significant of these enhancements is the APIsupport for third party mutipathing plugins. This provides a framework that enables the

EqualLogic MEM to intelligently route and efficiently load balance iSCSI traffic acrossmultiple NICs.

The EqualLogic MEM provides the following benefits:

Ease of install

Increased bandwidth

Reduced network latency

Automatic failure detection and failover

Automatic load balancing across multiple active paths

Automatic connection management

Multiple connections to a single iSCSI target

The EqualLogic MEM utilizes the same multipathing iSCSI vSwitch as VMwares Round

Robin multipathing. As part of Dells continuous efforts to help customers simplify theconfiguration of their IT environments, the iSCSI MPIO vSwitch configuration processfor the EqualLogic MEM has been reduced to either a single command with a few

parameters or a guided question and answer process. The MEM installation process isequally straightforward, requiring that only a single command be executed. The MEMcan also be installed using VMwares vSphere Update Manager.

Once installed, the EqualLogic MEM will automatically create iSCSI sessions to eachmember that a volume spans. As the storage environment changes, the MEM willrespond by automatically adding or removing iSCSI sessions as needed.

As storage I/O requests are generated on the ESXi hosts, the MEM will intelligentlyroute these requests to the array member best suited to handle the request. Thisresults in efficient load balancing of the iSCSI storage traffic, reduced network latency

and increased bandwidth.


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Deploying the EqualLogic MEM

Deploying the EqualLogic MEM consists of two steps:

Configuring a vSwitch for iSCSI multipathing

Installing the EqualLogic MEM

The entire process of creating the multipathing compatible vSwitch and installing theEqualLogic multipathing extension module can be quickly and efficiently completed.

Once deployed, it can provide both new and existing ESXi hosts with increasedperformance to EqualLogic storage resources.

Deployment Considerations: Requirements

The EqualLogic MEM has the following requirements:

VMware vSphere ESXi 4.1 or 5.x with Enterprise or Enterprise Plus licensing VMware CLI (Command-Line Interface) or VMware vMA (vSphere

Management Assistant) compatible with above version of ESXi Compatible EqualLogic array firmware, refer to Release Notes.

Prior to deploying the MEM the following steps should be completed:

1. The ESXi host(s) must be placed in maintenance mode.2. Download and install either the VMware vMA, or vSphere CLI. Refer to

VMwares documentation for installation and configuration details of these

tools.3. Download the Dell EqualLogic Multipathing Extension Module for VMware

vSphere (MEM) from the EqualLogic Support website. There are currently

two version of MEM; MEM 1.2 which supports versions 5.0, 5.1 and 5.5 ofESXi, and MEM 1.1.2 which supports versions 4.1, 5.0 and 5.1 of ESXi.Customers are encouraged to use the most current applicable version for

the version of ESXi they are using. The download will be a zip archivenamed EqualLogic-ESX-Multipathing-Module.zip4. Unpack the ZIP archive. It will contain the files:

dell-eql-mem-esx-.zip

Note: This is a VIB offline bundle and should not be unzipped.

MEM-Release_Notes.pdf

MEM-User_Guide.pdf

README.txt

setup.pl5. If using the vMA, upload setup.pl and the VIB offline bundle to the vMA.6. Retain the MEM-Release_Notes.pdf, MEM-User_Guide.pdf, and README.txt

files for reference.

Note: MEM 1.2 is only compatible with vSphere 5.x and certified on EqualLogicfirmware version 5.2. For prior versions of vSphere or firmware use MEM 1.1.x.


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Deployment Considerations: Storage Heartbeat on vSphere 5.0 and 4.1

In the VMware virtual networking model, certain types of vmkernel network traffic aresent out a default vmkernel port for each subnet. The iSCSI multipathing networkconfiguration requires that the iSCSI vmkernel ports use a single physical NIC as an

uplink. As a result, if the physical NIC that is being used as the uplink for the default

vmkernel port goes down, network traffic that is using the default vmkernel port willfail. This includes vMotion traffic, SSH access, and ICMP ping replies.

Though iSCSI traffic isnt directly affected by this condition, a side effect of thesuppressed ping replies is that the EqualLogic PS Series group will not be able toaccurately determine connectivity during the login process, and therefore a

suboptimal placement of iSCSI sessions will occur. In some scenarios, depending uponarray, server and network load, logins may not be completed in a timely manner. Toprevent this from occurring, Dell recommends that a highly available vmkernel port be

created on the iSCSI subnet serving as the default vmkernel port for such outgoingtraffic.

Note: This recommendation for using Storage Heartbeat applies only to vSphere 4.1

and 5.0. It is not necessary with the improvements in vSphere 5.1 and later.

Deployment Considerations: iSCSI Connection Count

The Dell EqualLogic MEM provides for increased bandwidth and lower latency accessto EqualLogic storage. This performance benefit is achieved through leveraging several

behaviors that are unique to the EqualLogic peer storage architecture. It is important tounderstand how the MEM achieves these performance gains, and the potential impactit can have if these considerations are not taken into account.

The MEM achieves its performance gains by creating multiple iSCSI connections toeach PS Series group member on which a datastore volume resides. Assuming the

MEMs default settings are in use, and depending on the configuration of theenvironment, there will be up to six iSCSI connections to a datastore volume. This is asignificant increase, when compared with VMwares Fixed Path policy, which utilizesone iSCSI connection per volume. This increase in connections must be planned for at

deployment time, and also, as the vSphere environment and its supporting EqualLogicstorage environment scales.

To calculate the number of iSCSI connections that the MEM will consume in a

particular environment, utilize the following formula:

Number of ESXi hosts * 2 (default iSCSI sessions per volume portion) * Number

of EqualLogic members in the pool (with a max value of 3) * Number ofvolumes

For example: In a vSphere environment with eight ESXi hosts, and using a two member

EqualLogic pool for hosting the ten volumes needed for virtual machines this wouldbe:

8 * 2 * 2 * 10 = 320 iSCSI connections

While this is within the 1024 iSCSI connection limit per pool of the firmware, it doesnot take into account other iSCSI connections to the EqualLogic storage pool from

other servers in the datacenter. Consideration should also be given to how this virtual


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environment may grow in the future with respect to additional ESXi hosts, datastorevolumes and additional EqualLogic members.

The release of EqualLogic 6.0 firmware provided for enhanced communication with

the MEM. This enables the array to notify the MEM of the number of total iSCSIconnections to the pool from all sources. Should the number of iSCSI connections to

the pool begin to approach the limit, then the MEM will reduce the number of iSCSIsession it is creating to the array, while still maintaining redundancy.

Depending on the overall environment, and future requirements, changes may need tobe made to one or more of the following if there are concerns about the iSCSI

connection count growing too large:

The MEM parameters membersessi ons, vol umessessi ons ort ot al sessi ons: see the Installation and User Guide for details.

The number of volumes: By increasing the size of a given volume, more virtualmachines can reside on it, thereby reducing the total number of volumesneeded. With vSphere 5.0 datastore size is no longer restricted to 2TB.

Reconfigure larger clusters into multiple smaller clusters. By splitting large

clusters into smaller clusters, the number of hosts accessing particular volumesis reduced, thereby reducing the number of iSCSI connections consumed.

The configuration of EqualLogic members: reducing the number of EqualLogicmembers per pool, and increasing the number of pools, will increase thenumber of available iSCSI connections.

For more information on this topic read TR1072 Dell EqualLogic PS Arrays Scalabilityand Growth in Virtual Environments http://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19992296.aspx

As with all rules there are exceptions. The MEM iSCSI connection algorithm works to

avoid creating unnecessary sessions while still maintaining redundancy. With the

PS6110 and PS-M4110, both of which have only one 10Gb Ethernet port, this results infewer iSCSI connections being created when compared to arrays with multiple

Ethernet ports per controller. With the PS6110 and PS-M4110, if they are in a singlemember pool, MEM will create two iSCSI connections per volume, for redundancy. In atwo or three member pool MEM will create a single iSCSI connection per member,

resulting in a total of two or three iSCSI connections being created per volume. Thisbalances the bandwidth and throughput from an individual ESXi host with that of anindividual EqualLogic member.

Deployment Considerations: iSCSI Login Timeout on vSphere 5.x

The default value of 5 seconds for iSCSI logins on vSphere 5.x is too short in some

circumstances. For example: In a large configuration where the number of iSCSIsessions to the array is close to the limit of 1024 per pool. If a severe network

disruption were to occur, such as the loss of a network switch, a large number of iSCSIsessions will need to be reestablished. With such a large number of logins occurring,some logins will not be completely processed within the 5 second default timeout

period.
http://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19992296.aspxhttp://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19992296.aspxhttp://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19992296.aspxhttp://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19992296.aspxhttp://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19992296.aspx


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Dell therefore recommends applying patch ESXi500-201112001 and increasing the ESXi

5.0 iSCSI Login Timeout to 60 seconds to provide the maximum amount of time forsuch large numbers of logins to occur.

If the patch is installed prior to installing the EqualLogic MEM, the MEM installer will

automatically set the iSCSI Login Timeout to the Dell recommended value of 60

seconds.

The iSCSI Login Timeout value can also be set using esxcli with the following syntax:

esxcl i i scsi adapt er par am set - - adapt er =vmhba - - key=Logi nTi meout- - val ue=60

See VMware KB 2009330 for additional information.

Deployment Considerations: Best Practices parameter in MEM 1.2

One of the new options in version 1.2 of MEMs setup.pl script for configuring the ESXi

hosts iSCSI vSwitch is the - - bestpr act i ce parameter. Using this parameter will

change some of the ESXi hosts settings from the defaults.With the MEM 1.2 release the settings that are changed are:

Disabling Delayed ACK: Delayed ACK is a TCP/IP method of allowing segmentacknowledgements to piggyback on each other or other data passed over aconnection with the goal of reducing IO overhead. One side effect of delayed ACK is

that if the pipeline isnt filled, acknowledgement of data will be delayed. In SANHQ thiscan be seen as higher latency during lower I/O periods. Latency is measured from thetime the data is sent to when the acknowledgement is received. Since we are talkingabout disk I/O any increase in latency can result in poorer performance. Additional

information can be found in VMware KB 1002598.

Note: While iSCSI Login Timeout is considered a best practice, it is also consider a

requirement, and therefore will always be set to 60 seconds during installation.


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Configuring an iSCSI vSwitch for Multipathing

As previously mentioned, the EqualLogic MEM utilizes the same multipathing vSwitchas VMwares Round Robin multipathing. Therefore if the ESXi hosts are alreadyconfigured for Round Robin this step can be omitted. However, if the ESXi hosts are

configured for Fixed Path, the iSCSI initiator and associated vSwitch should be removed

before continuing. Those who have previously configured Round Robin multipathingwill appreciate the powerful functionality and the ease of use the MEMs setup.pl script

provides when compared to the manual configuration process.

Note: The instructions provided here refer to using the vMA, however the syntax is the

same whether the vMA or CLI is used. The optional parameters --user name and --passwor d have been excluded from the examples below for clarity. If not included andvi-fastpass is not configured, then the user will be prompted to provide the usernameand password.

1. Connect to the vMA and change directory to where the setup.pl wasuploaded to.

2. The simplest method of creating a multipathing iSCSI vSwitch is to invoke

the setup.pl in Interactive Mode.

set up. pl - - conf i gur e - - ser ver =hostname

In this configuration mode a series of questions are posed to the user, and

in many instances default options presented. To accept a default, pressenter, as shown in the example below:

Interactive Mode configuration

set up. pl - - conf i gur e - - ser ver =10. 124. 6. 223Do you wi sh t o use a st andard vSwi t ch or a vNetwork Di st r i but ed Swi t ch( vSwi t ch/ vDS) [ vSwi t ch] :Found exi st i ng swi t ches vSwi t ch0.vSwi t ch Name [ vSwi t chI SCSI ] :Whi ch ni cs do you wi sh t o use f or i SCSI t r af f i c? [ vmni c1 vmni c2 vmni c3] :vmnic2 vmnic3I P addr ess f or vmkni c usi ng ni c vmni c2: 192.168.0.215I P addr ess f or vmkni c usi ng ni c vmni c3: 192.168.0.216What I P addr ess woul d you l i ke t o use f or t he hi ghl y avai l abl e hear t beatvmkni c ( opt i onal ) ?: 192.168.0.214Netmask f or al l vmkni cs [ 255. 255. 255. 0] :What MTU do you wi sh t o use f or i SCSI vSwi t ches and vmkni cs? Bef or ei ncr easi ng t he MTU, ver i f y the set t i ng i s support ed by your NI Cs andnetwork swi t ches. [ 1500] : 9000What pr ef i x shoul d be used when creat i ng VMKernel Por t gr oups? [ i SCSI ] :

The SW i SCSI i ni t i at or i s not enabl ed, do you wi sh t o enabl e i t ? [ yes] :

What PS Gr oup I P address woul d you l i ke t o add as a Send Target di scoveryaddr ess ( opt i onal ) ?: 192.168.0.200What CHAP user woul d you l i ke t o use t o connect t o vol umes on t hi s gr oup( opt i onal ) ?: BLUEclusterWhat CHAP secr et woul d you l i ke to use t o connect t o vol umes on t hi sgr oup ( opt i onal ) ?:


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Conf i gur i ng i SCSI net wor ki ng wi t h f ol l owi ng set t i ngs:Usi ng a st andar d vSwi t ch ' vSwi t chI SCSI 'Usi ng NI Cs ' vmni c2, vmni c3'Usi ng I P addr esses ' 192. 168. 0. 215, 192. 168. 0. 216'Cr eat i ng a hi ghl y avai l abl e vmker nel por t wi t h I P ' 192. 168. 0. 214'Usi ng net mask ' 255. 255. 255. 0'

Usi ng MTU ' 9000'Usi ng pr ef i x ' i SCSI ' f or VMKer nel Por t gr oupsUsi ng SW i SCSI i ni t i at orEnabl i ng SW i SCSI i ni t i at orAddi ng PS Ser i es Gr oup I P ' 192. 168. 0. 200' wi t h CHAP user

' CHAPuser ' t o Send Tar get s di scover y l i st .The f ol l owi ng command l i ne can be used t o per f or m t hi s conf i gurat i on:set up. pl - - conf i gur e - - ser ver =10. 124. 6. 223 - - vswi t ch=vSwi t chI SCSI - -mt u=9000 - - ni cs=vmni c2, vmni c3 - - i ps=192. 168. 0. 215, 192. 168. 0. 216 - -hear t beat=192. 168. 0. 214 - - net mask=255. 255. 255. 0 - - vmkernel =i SCSI - -nohwi scsi - - enabl eswi scsi - - gr oupi p=192. 168. 0. 200 - - chapuser=BLUEcl ust erDo you wi sh t o pr oceed wi t h conf i gur at i on? [ yes] :

Note that the CHAP secret is not displayed as part of the command line thatInteractive Mode will generate.

3. As the script executes, it will provide status notifications as it proceedsthrough several steps to create the multipathing iSCSI vSwitch.

4. Once complete a multipathing iSCSI vSwitch, like the example shown

below, will be created on the ESXi host.

A detailed list of all the parameters options and their usage can be found in the

EqualLogic MEM Installation and User Guide. Additional configuration examples can befound in Appendix A.

Note: The example above was generated using MEM 1.1.1 and vSphere 5.1, the output

may differ slightly with other combinations.


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Unattended Mode configuration

While setup.pl scripts Interactive Mode is extremely helpful, using it to configureall the hosts in a cluster is not the most efficient means of performing this task.Instead it is possible to pass to the setup.pl script the values for the variousparameters.

At the end of the Interactive Mode configuration shown above, it presents the resultingcommand line from the Interactive Mode questions and answers. This is shown againhere:

set up. pl - - conf i gur e - - ser ver =10. 124. 6. 223 - - vswi t ch=vSwi t chI SCSI- - mt u=9000 - - ni cs=vmni c2, vmni c3 - - i ps=192. 168. 0. 215, 192. 168. 0. 216- - hear t beat=192. 168. 0. 214 - - net mask=255. 255. 255. 0 - - vmkernel =i SCSI- - nohwi scsi - - enabl eswi scsi - - gr oupi p=192. 168. 0. 200- - chapuser=BLUEcl ust er

Using this as an example, and by modifying the hostname and IP informationadditional ESXi hosts can be easily provisioned with the same vSwitch configuration.For example:

set up. pl - - conf i gur e - - ser ver =10.124.6.224 - - vswi t ch=vSwi t chI SCSI- - mt u=9000 - - ni cs=vmni c2, vmni c3 - - i ps=192.168.0.225, 192.168.0.226- - hear t beat =192.168.0.224 - - net mask=255. 255. 255. 0 - - vmkernel =i SCSI- - nohwi scsi - - enabl eswi scsi - - gr oupi p=192. 168. 0. 200- - chapuser=BLUEcl ust er - - chapsecr et=BLUEsecr et

Note that the CHAP secret is not displayed as part of the command line that InteractiveMode generates, but has been added to the example above. If not included, setup.pl

will prompt for the secret at run time.

Depending upon the required configuration of the multipathing iSCSI vSwitch

additional parameters maybe required or removed. For a full listing of the parametersand their defaults see the Configuring Your Network for the MEM Pluginin the DellEqualLogic MEM Installation and User Guide.


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Installing the EqualLogic MEM

The EqualLogic MEM can be installed using the command line tools, CLI or vMA, orwith VMware Update Manager (VUM). The command line tools are used in thisexample. See Appendix C for install instructions on using VUM for installation.

Setup.pl is a Perl script wrapper around a number of VMware CLI commands, andhence provides administrators with a similar installation process regardless of vSphereversion. However there are some differences, which are listed here:

On vSphere 5.x:

The multipathing functionality is available immediately after a fresh install;

however hostd needs to be restarted prior to the new esxcli controlling andreporting commands being available.

Prior to installation setup.pl will copy the VIB to the first datastore it finds;

optionally a particular datastore can be specified by using the - - dat ast or eparameter. Due to API limitations the VIB is not deleted by setup.pl.

On vSphere 4.1:

A reboot is required before the plugins multipathing functionality is available.

Note: When performing an upgrade or uninstall of the MEM a reboot is required on allversions of vSphere.

1. Using the vMA or vSphere CLI, execute the following command for each

host the MEM is to be installed to:

set up. pl - - i nstal l - - server=hostname

It may take a few minutes to install the module to the ESXi host.

2. Depending on the version of vSphere this next step will differ:a. On a vSphere 5.x host, the plugins multipathing functionality is available

for use.

To enable of the new esxcli commands restart the hostd service byexecuting the following command issued on the host, as documented in

VMware KB2004078:

/ et c/ i ni t . d/ hostd r estar t

b. On a vSphere 4.1 host, a reboot is required before the plugins

multipathing functionality is available. To automatically reboot the ESXi

host once the install is complete include the - - r eboot parameter.3. To verify the availability of a the EqualLogic MEM execute:

vSphere 5.x: esxcl i st or age nmp psp l i st

vSphere 4.1: esxcl i nmp psp l i st

This will display a list of the PSP installed on the host, as shown below:

Name Descr i pt i onDELL_PSP_EQL_ROUTED Del l Equal Logi c Pat h Sel ect i onVMW_PSP_MRU Most Recent l y Used Pat h Sel ect i onVMW_PSP_RR Round Robi n Pat h Sel ect i onVMW_PSP_FI XED Fi xed Path Sel ect i on


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Verification of MEM iSCSI Session Creation

By default the EqualLogic MEM will claim any existing and new EqualLogic volumesand create the additional iSCSI session used by the MEM to route the iSCSI data. Toverify these additional sessions, perform the following steps:

1. In the vSphere client click on the Configuration tab. In the Hardware pane

select Storage.2. Right click on the datastore, select Properties, and then click the Managed

Paths button.

3. In the example above the Path Selection Policy has been set to use the MEM,as path selection shows DELL_PSP_EQL_ROUTED. Four sessions to the

volume have been created, as the volume resides in a two member storagepool.

4. This can also be verified from the array web GUI by clicking on the volumesConnections tab. As shown in the example below, two iSCSI sessions havebeen established from each of the VMkernel Ports on the ESXi host to the

volume.


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Advanced iSCSI connection configuration parameters

There are minimal configuration parameters that are needed with the EqualLogic MEM.The few that do exist are used to alter the runtime behavior of the EqualLogic HostConnection Manager, EHCM, which manages the iSCSI sessions to the EqualLogicvolumes. For information on all parameters refer to the Dell EqualLogic MEM

Installation and User Guide.Three configuration parameters affect the number of iSCSI sessions that will becreated:

totalsessions: The maximum total number of session that may be created to all

EqualLogic volumes that the host can access. Default value: 512

volumesessions: The maximum number of session that may be created to anyindividual EqualLogic volume. Default value: 6

membersessions: The maximum number of session that may be created to theportion of a volume that resides on a single member. Default value: 2

When determining how many sessions to create, EHCM chooses a value that meets all

these constraints. The default values were chosen to provide good performancewithout unnecessarily consuming excess resources. In the majority of installations,these settings do not need to be changed from the defaults.

Prior to altering these values it is strongly advised that an administrator fully

understand the impact of such a change on the total number of iSCSI connections. Forinformation on the number of iSCSI connections that particular firmware versions canhandle at a per pool and group level, refer to the release notes for that firmware. Referto VMwares documentation for details on vSphere limits that may apply.

TheDeployment Considerations: iSCSI Connection Countsection of this technicalreport includes a formula for calculating the iSCSI connection count based on thenumber of hosts, sessions per volume portion, EqualLogic members in the pool, and

the number of volumes the hosts are connected to. One should also take into accountconnections from other systems such as; other physical servers, virtual machines withiSCSI within the guest connections, and backup servers, as well as short livedconnections used by xcopy, which is used by the vSphere VAAI Full Copy primitive and

replication, in the total iSCSI connection count.

Increasing the default values

In some instances there may be a preference to increase the number of iSCSIconnections. Typically these preferences only exist in lab settings, where the desire is

to benchmark I/O to an individual volume or in other ways test the limits.

In such a configuration it is possible that the default membersession value is limitingthe number of iSCSI connections to fewer then the number of VMkernel ports bound

to the iSCSI initiator. To utilize all the VMkernel ports bound to the iSCSI initiator,membersessions should be increased to a sufficiently high value to enable EHCM tocreate iSCSI connections through all bound VMkernel ports.

Generally this increase would not be beneficial in a production environment. In aproduction environment multiple volumes are used, and EHCM would, in aggregate,


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create and balance an optimal number of iSCSI sessions, effectively utilize all of thenetwork ports

Decreasing the default values

In large configurations it is possible to exceed the iSCSI connection limits of the array

firmware. In such cases it is necessary to reduce the number of iSCSI connections tobe within limits. This can be achieved in several ways including:

Reduce the number of volumes: By increasing the size of a given volume, more

virtual machines can reside on it, thereby reducing the total number of volumesneeded. With vSphere 5.0 datastore are no longer restricted to 2TB.

Reconfigure larger clusters into multiple smaller clusters. By splitting a large

cluster into smaller clusters, the number of hosts accessing particular volumesis reduced, thereby reducing the number of iSCSI connections consumed.

Alter the configuration of EqualLogic group: reducing the number of EqualLogic

members per pool, and increasing the number of pools, will increase thenumber of available iSCSI connections.

However, these changes typically take some time to implement. Altering the EHCM

parameters provides a means of quickly reducing the iSCSI connection to be withinlimits. However, depending on the overall environment configuration and I/Oworkload, a drop in overall performance may be observed.

totalsessions: This parameter is defaulted to a maximum of 512, and can belowered to 64. It is the maximum number of iSCSI connections that EHCM willcreate from this individual ESXi host to all EqualLogic arrays. If an additional

volume is added to the host EHCM will automatically rebalance the sessions toinclude the new and existing volumes, yet not consume more than thetotalsessions limit.

volumesessions: This parameter is defaulted to a maximum of 6, and can belowered to 1. It is the maximum number of iSCSI connections that EHCM willmake from this individual ESXi host to each individual EqualLogic volume,

regardless of the number of array members the volume may span as the groupexpands. This value applies to all volumes that the host accesses, and cannot bespecified to affect only particular volumes. As additional members are added to

the pool, and volumes are distributed to include this new member, EHCM willcreate additional sessions to the volume within this limit.

membersessions: This parameter is defaulted to a maximum of 2, and can be

lowered to 1. It is the number of iSCSI connections that EHCM will make fromthis individual ESXi host to the portion of a volume that resides on an individualEqualLogic member. Setting membersessions to 1 will halve the iSCSI

connection count from the ESXi host to the array. However, this effectivelydisables the Least Queue Depth part of the MPIO algorithm, as there is onequeue to each portion of the volume to choose from. The Intelligent Routingpart of the algorithm remains in use, so I/O requests will be efficiently directed

to the appropriate member.


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Setting the EHCM configuration values under vSphere 5.x

For vSphere 5.0 EqualLogic have added to the existing esxcli command set a numberof commands that can be used to control and report on the status of the MEM. It isthrough these commands that the EHCM parameters are changed.

esxcli can be executed remotely from the vMA, CLI, or directly on the ESXi host

The syntax of this command is:

esxcl i equal l ogi c par am set - - name=parameter_name

- - val ue=parameter_value

For example:

esxcl i equal l ogi c par amset - - name=membersessi on - - val ue=1

To query the current EHCM values use the following syntax:

esxcl i equal l ogi c par am l i st

Setting the EHCM configuration values under vSphere 4.1

For vSphere 4.1 the setup.pl script is used to change and query the EHCM configurationvalues. It can be executed from the vMA or CLI, but not directly on the ESXi host.

The syntax of this command is:

set up. pl - - set par am - - name=parameter_name

- - val ue=par amet er _val ue - - server =hostname

For example:

set up. pl - - set param - - name= membersesi on - - val ue=1

- - ser ver =host nameTo query the current EHCM values use the following syntax:

set up. pl - - l i stparam - - server=hostname


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Summary

The EqualLogic MEM, through its intelligent routing and load balancing, can provide areduction in network latency and an increase in bandwidth to PS Series Storage arrays.Through automated setup and host connection management, the MEM also reduces

the steps for deployment and ongoing management of advanced vSphere iSCSI

configurations.

Technical Support and Customer Service

Dell support service is available to answer your questions about PS Series SAN arrays.

Contacting Dell

1. If you have an Express Service Code, have it ready.The code helps the Dell automated support telephone system direct your callmore efficiently.

2. If you are a customer in the United States or Canada in need of technicalsupport,

call 1-800-945-3355. If not, go to Step 3.

3. Visitsupport.dell.com/equallogic.

4. Log in, or click Create Account to request a new support account.

5. At the top right, click Contact Us, and call the phone number or select the linkfor the typeof support you need.
http://support.dell.com/equallogichttp://support.dell.com/equallogichttp://support.dell.com/equallogichttp://support.dell.com/equallogic


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Appendix A: Example iSCSI vSwitch configurations

This appendix provides some examples of the additional parameters used with thesetup.pl configuration script. A detailed list of all the parameters and their usage can befound in the EqualLogic MEM Installation and User Guide

Overriding hardware iSCSI offload default utilization

With vSphere 4.1 and above, ESXi can utilize the iSCSI offload capabilities of theBroadcom NetXtreme II network adaptors, resulting in significantly lower softwareiSCSI CPU utilization. The setup.pl configuration script will, by default, utilize this iSCSIoffload capability if it is present. If there is a preference not to use the iSCSI offload

capability this must be specified when configuring the iSCSI vSwitch. This is shownbelow:

set up. pl - - conf i gur e - - ser ver =172. 17. 5. 121 - - ni cs=vmni c2, vmni c3- - i ps=192. 168. 0. 215, 192. 168. 0. 216 --nohwiscsi

Utilizing a vNetwork Distributed Switch

With Enterprise Plus licensing VMware provides a virtual switch which spans many ESXihosts. This abstracts the configuration of individual vSwitches on the host level andenables centralized management through vSphere vCenter Server. If utilizing a

vNetwork Distributed Switch for iSCSI traffic the - - vds parameter must be specified.Should the name of the vNetwork Distributed Switch differ from the default utilized by

the configuration script, it can be specified using the -vswitch parameter. This isshown below:

set up. pl - - conf i gur e - - ser ver =172. 17. 5. 121 - - ni cs=vmni c2, vmni c3- - i ps=192. 168. 0. 215, 192. 168. 0. 216 - vswi t ch vdsI SCSI --vds

Enabling Jumbo Frames

With the vSphere release of ESXi support for Jumbo Frames has been extended to

VMkernel traffic, which includes the iSCSI stack. To utilize Jumbo Frames they must beenabled on all networking components used. By default the setup.pl script uses anMTU of 1500 when creating the iSCSI vSwitch and VMkernel interfaces. To use a larger

value specify it as demonstrated in the example below.

set up. pl - - conf i gur e - - ser ver =172. 17. 5. 121 - - ni cs=vmni c2, vmni c3- - i ps=192. 168. 0. 215, 192. 168. 0. 216 -mtu=9000

Setting the iSCSI discover addressIt is possible to specify the group IP of an array to be set as the Send Targets discoveryaddress for the iSCSI initiator.

set up. pl - - conf i gur e - - ser ver =172. 17. 5. 121 - - ni cs=vmni c2, vmni c3- - i ps=192. 168. 0. 215, 192. 168. 0. 216 -groupip=192.168.0.200


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Appendix B: Installing the MEM with VMware Update Manager

VMware Update Manager has the ability to install and upgrade third party packages tothe ESXi hosts. This enables administrators to not only manage the patching andupdating of ESXi hosts but also to update third party packages installed on the ESXi

hosts.

Installing the MEM consists of four major steps:

Steps 1-3 need to be done once per version release of the MEM

o Importing the MEM to the Patch Repository

o Creating an extension baseline that includes the MEM

o Attaching the baseline to the environment

Step 4 needs to be done for each host in the cluster, or datacenter

o Installing the MEM to each host

Step 1: Importing the MEM to the Patch Repository

1. Download Dells EqualLogic MEM from the EqualLogic Support website.

2. Unpack the ZIP archive. Do not unpack the embedded zip file, this is a VIBoffline bundle and is expected to be in this format.

3. From the vSphere client Home section, select Update Manager from underSolutions and Applications.

4. From the Admin View select the Patch Repository tab and then click onImport Patches to start the Import Patches wizard.

5. Click on Browse and browse to where the Zip archive was unpacked andselect the embedded Zip file named dell-eql-mem-.zip,click Open and then click Next.

6. The Import Patches wizard will upload and analyze the file; this may take afew minutes, and will then present a Confirm Import page. Verify the details

are as expected and click Finish.

Step 2: Creating an Extension Baseline

7. From the vSphere client select Update Manager -> Admin View and selectthe Baselines and Groups tab.

8. On the Baselines and Group tab, in the Baseline section, click Create tostart the New Baseline wizard.


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9. Provide the baseline with a suitable name and optional description, select

the baseline type Host Extension and then click Next, as shown in theexample below.

10. From the list of extensions, highlight the Dell EqualLogic iSCSI MEM 1.1.0,click the selection button and then click Next. If there are a large number ofextensions in the repository, use EqualLogic as a keyword for filtering.

11. On the Ready to Complete page of the wizard verify that the information iscorrect, and click Finish.

Step 3: Attaching the Extension Baseline12. From the vSphere client select Update Manager -> Compliance View.13. From the tree pane, on the left, select the Datacenter, Cluster, or Host that

the MEM Extension Baseline is to be attached to, and then click on Attachto start the Attach Baseline wizard.

14. Select the MEM extension baseline created above and click on Attach toattach the Extension Baseline to the vSphere Datacenter, Cluster or Host.

Step 4: Installing the MEM

15. From the vSphere client select Update Manager -> Compliance View.

16. In the Attached Baselines pane highlight the MEM extension baseline thatwas attached earlier and click the Remediate button to start the

Remediation wizard.17. On the Remediation Selection page of the wizard verify that the correct

baseline is listed, and unselect any host to which the EqualLogic MEM is notto be installed to at this time. Click Next to continue.

18. The Patches and Extensions page lists the patches and extensions to beapplied. Click Next to continue.


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19. On the Schedule page change the Task Name, if desired, and optionallyprovide a Task Description. There is also the option to schedule thedeployment for a future time and date, rather than Immediately which is

selected by default. Click Next to continue.20. On the Host Remediation Options and Cluster Remediation Options pages

there are options for altering the behaviors of the virtual machines, hosts,and cluster during the install. Refer to the vCenter Update ManagerInstallation and Administration Guidefor details. Click Next to continue.

21. On the Ready to Complete page, verify that the information is correct, andclick Finish. Unless the task was schedule to run at a later time it will beimmediately executed.

22. As the task is been executed it will display status updates in the RecentTasks pane of the vSphere client. If several host were selected the task willexecute against one host at a time, until the MEM has been installed on all

the selected hosts.23. Once the task has been completed the MEM will have been installed or

updated on all the hosts selected.

24. As shown in the screenshot below, the vCenter Update Manager canprovide a clear graphical view of which ESXi hosts the MEM is installed orupdated on, and which hosts it has yet to be installed or updated on.

Note: vCenter Update Manager is only capable of install the MEM. vMA or vCLI willneed to be utilized to configure the iSCSI vSwitch for the MEM.

Documents

TR1074 vSphere MEM