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Port BindingT e c h n i c a l W h i T e P a P e R

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Tb of cotts

Multipathing or Sotware iSCSI 3Confguring vmknic-Based iSCSI Multipathing 3

a) Confguring the Network 3

1. Using GUI 3

2. Using CLI 6

b) Enabling the iSCSI Sotware Adapter 7

1. Using GUI 7

2. Using CLI 9

c) Activating vmknic-Based Multipathing or Sotware iSCSI 9

1. Confguring Port Binding on vSphere 5.0 Using GUI 9

2. Confguring Port Binding on vSphere 5.0 Using CLI 12

3. Confguring Port Binding on vSphere 4.x Using CLI 12

iSCSI Re-login 12

Veriying Multipath Confguration 13

1. Veriying the iSCSI LUN Confguration 13

2. Veriying vmknic-Based Multipath Failover 13

3. Veriying Load Balancing Using the Round-Robin Policy 14

Conclusion 15

About the Author 15

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Multipathing Coniguration or Sotware iSCSIUsing Port Binding

Multipathing or Sotware iSCSIMultipathingbetweenaserverandstoragearrayprovidestheabilitytoload-balancebetweenpathswhenall

pathsarepresentandtohandleailuresoapathatanypointbetweentheserverandthestorageMultipathingisadeactostandardormostFibreChannelSANenvironmentsInmostsotwareiSCSIenvironments

multipathingispossibleattheVMkernelnetworkadapterlevelbutnotthedeaultconguration

InaVMwarevSphereenvironmentthedeaultiSCSIcongurationorVMwareESXiserverscreatesonlyone

pathromthesotwareiSCSIadapter(vmhba)toeachiSCSItargetToenableailoveratthepathlevelandto

load-balanceI/Otracbetweenpathstheadministratormustcongureportbindingtocreatemultiplepaths

betweenthesotwareiSCSIadaptersonESXiserversandthestoragearray

WithoutportbindingalliSCSILUNswillbedetectedusingasinglepathpertargetBydeaultESXwilluse

onlyonevmknicasegressporttoconnecttoeachtargetandyouwillbeunabletousepathailoverortoload-

balanceI/ObetweendiferentpathstotheiSCSILUNsThisistrueeveniyouhavecongurednetworkadapter

teamingusingmorethanoneuplinkortheVMkernelportgroupusedoriSCSIIncaseosimplenetwork

adapterteamingtracwillberedirectedatthenetworklayertothesecondnetworkadapterduring

connectivityailurethroughtherstnetworkcardbutailoveratthepathlevelwillnotbepossiblenorwill

loadbalancingbetweenmultiplepaths

Someotheuserguidesanddocumentationreertovmknic-basedsotwareiSCSImultipathingasport

bindingorsimplyassotwareiSCSImultipathingThispaperprovidesanoverviewohowtoenablevmknic-

basedsotwareiSCSImultipathingaswellastheprocedurebywhichtoveriyportbindingconguration

Confguring vmknic-Based iSCSI MultipathingToenablevmknic-basedsotwareiSCSImultipathingyoumust

CreatetwoVMkernelportgroupsandconnectoneuplinktoeachofthem.

BindeachVMkernelnetworkadaptertothesoftwareiSCSIadapter.ThenrunarediscoveryofiSCSItargetsto

detectmultiplepathstothem

Reertotheollowingsectionstolearnthenetworkcongurationandportbindingprocedurerequiredtoenable

vmknic-basedmultipathingorsotwareiSCSI

a) Confguring the NetworkEnablingmultipathingremovestheabilitytoroutetostorageThestorageandtheVMkernelportmusthavean

IPaddressinthesamenetwork

InthevSpherereleaseyoucanuseGUIwizardorCLIcommandstocongureyournetwork;invSpherex

youcanuseonlyCLIcommands

1UsingGUI

Toenablevmknic-basedmultipathingorsotwareiSCSIitisrecommendedthatyouhavetwoormorephysical

networkadaptersoriSCSIonyourhostmachine

1) Connect to the ESXi server using the VMware vSphere Client

2) Click the Confguration tab > Networking.

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3) Click Add Networking.

4) Select VMkernel and click Next.

5) Select Create a vSphere standard switch to create a new vSwitch.

6) Select all the adapters you want to congure or iSCSI trac and click Next.

7) Provide a Network Label or the VMkernel port group and click Next.

8) Speciy the IP address settings and click Next.

9) Review the details on the Summary screen and click Finish.

NexttocreateanadditionalVMkernelportgrouptocongureportbindingcompletetheollowingsteps

1) Click the Properties tab o the vSwitch you created or iSCSI.

2) Create additional VMkernel ports or all network adapters that you connected by selecting the Add tab

under the Ports tab in the vSwitch Properties dialog box.

3) Select VMkernel and click Next.

4) Provide a Network Label or the VMkernel port group and click Next.

5) Speciy the IP address settings and click Next.

6) Review the details on the Summary screen and click Finish.

YoucanalsocreateVMkernelportgroupsondiferentvSwitchesHoweveriyourVMkernelnetworkadapters

areonthesamesubnettheymustbeconguredonthesamevSwitch

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AllnetworkadaptersthatyouaddedtothevSwitchwillappearasactiveoreachVMkernelportonthevSwitch

EnsurethatyouoverridethiscongurationsothateachVMkernelportmapstoonlyoneactiveadapter

1) In the Ports tab o the vSwitch Properties dialog box, select a VMkernel port and click Edit.

2) Click the NIC Teaming tab and check Override switch ailover order.

3) Keep only one adapter under Active Adapters and use Move Down to move other adapters under

Unused Adapters.

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4) Repeat steps 13 or each VMkernel port on the vSwitch, ensuring that each port has its own unique

active adapter.

2UsingCLI

RuntheollowingcommandstocreatethevSwitchandVMkernelportgroupsaswellastomapeachVMkernel

porttooneactiveadapter

1) Create the vSwitch: esxcfg-vswitch -a iscsivSwitch.

2) Add the rst uplink to the vSwitch: esxcfg-vswitch -L vmnic4 iscsivSwitch.

3) Add the rst port group on the vSwitch: esxcfg-vswitch -A iSCSI-PG1 iscsivSwitch.

4) Add the second uplink to the vSwitch: esxcfg-vswitch -L vmnic5 iscsivSwitch.

5) Add the second port group on the vSwitch: esxcfg-vswitch -A iSCSI-PG2 iscsivSwitch.

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6) Map each VMkernel port to use only one active adapter and to move the second network adapter to the

unused adapter list: esxcfg-vswitch -N vmnic4 -p iSCSI-PG1 iscsivSwitch.

7) Map each VMkernel port to use only one active adapter and to move the second network adapter to the

unused adapter list: esxcfg-vswitch -N vmnic5 -p iSCSI-PG2 iscsivSwitch.

8) Assign an IP address to the rst port group: esxcfg-vmknic -a -i 192.168.100.1 -n

255.255.255.0 iSCSI-PG1.

9) Assign an IP address to the second port group: esxcfg-vmknic -a -i 192.168.100.2 -n

255.255.255.0 iSCSI-PG2.

b) Enabling the iSCSI Sotware Adapter

1UsingGUI

ToaccessiSCSItargetsyoumustenablethesotwareiSCSIinitiatorontheVMwareESXiserver

Procedure

1) Connect to the ESXi server using vSphere Client.

2) Click Confguration > Storage Adapters.

3) Enable the iSCSI sotware adapter.

a. For ESXi server releases prior to vSphere 5.0, iSCSI Sotware Adapter is listed under the

Storage Adapters tab.

i. Select iSCSISotware Adapter and click Properties.

ii. Under the General tab, click Confgure.

iii. Check Enabled to enable the initiator.

iv. To change the deault iSCSI initiator name, enter iSCSI initiator name in the iSCSI Name box.

b. For vSphere 5.0, you must add iSCSI Sotware Adapter to the StorageAdapterscategory

i. Click Confguration > Storage Adapters.

ii. Click Add and check Add Sotware iSCSI Adapter.

iii. To change the deault iSCSI initiator name, enter iSCSI initiator name in the iSCSI Name box under

the Confgure tab in the iSCSI Sotware Adapter Properties window.

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4) Enter the iSCSI target address in Static/Dynamic Discovery.

Dynamic Discovery Speciy the addresses orSend Targets discovery. The iSCSI initiator sends a Send Targets

request to each o the specifed addresses, and the discovered targets are added to the static discovery list.

Static Discovery A list o IP addresses and iSCSI names o targets to connect to. This list can be flled in based

on dynamic Send Targets requests or entered individually. This is a list o targets with which ESX attempts to

establish sessions.

5) Click Close to nish iSCSI initiator conguration.

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2UsingCLI

Runtheollowingcommands

1) Enable the sotware iSCSI: esxcfg-swiscsi e

2) To change the deault iSCSI initiator name, set the initiator iqn:

- esxcli iscsi adapter set --name iqn.1998-01.com.vmware:esx-host01-64ceae7s -A vmhbaXX

3) Add the iSCSI target discovery address:

- esxcli iscsi adapter discovery sendtarget add -a 192.168.100.13:3260 -A vmhbaXX

NOTE: vmhbaXX is the sotware iSCSI adapter vmhba ID. To fnd the vmhba ID, you can use the command

esxcg-scsidevs-a and check or the vmhba ID o iSCSI sotware adapter.

c) Activating vmknic-Based Multipathing or

Sotware iSCSIVMwarevSpherehasaddedanewUIinteracetosupportmultipathingcongurationorthesotwareiSCSI

adapterusingportbinding(EarlierESX/ESXireleaseshadonlythecommand-lineinterace(CLI)optionto

congureportbinding)

1ConfguringPortBindingonvSphere50UsingGUI

a) Connect to the ESXi server using vSphere Client.

b) Click the Confguration tab and select Storage Adapters.

c) Select iSCSI Sotware Adapter and click Properties.

d) Click the Network Confguration tab and click Add to bind the VMkernel network adapter to the sotware

iSCSI adapter.e) The bind with the VMkernel adapter window is displayed, listing all the VMkernel adapters compatible with

iSCSI port binding requirements. Select the VMkernel network adapter you want to bind to the sotware

iSCSI adapter and click OK.

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) Repeat steps d) and e) until you bind all the required VMkernel adapters to the iSCSI adapter.

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NOTE: The port group policy status might report as noncompliant or the VMkernel network adapter or the

ollowing reasons:

TheVMkernelnetworkadapterisnotconnectedtoanactivephysicalnetworkadapteroritisconnectedto

morethanonephysicalnetworkadapter.

TheVMkernelnetworkadapterisconnectedtostandbyphysicalnetworkadapters.

Theactivephysicalnetworkadaptergotchanged.

g) Close the iSCSI Initiator Properties window.

h) Select the sotware iSCSI adapter and run Rescan to veriy that multiple paths are available or iSCSI LUNs.

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2ConfguringPortBindingonvSphere50UsingCLI

RuntheollowingcommandsromthevSpherehostCLItobindtheVMkernelnetworkadaptertothe

iSCSIadapter

- esxcli iscsi networkportal add --nic vmk0 --adapter vmhbaXX

- esxcli iscsi networkportal add --nic vmk1 --adapter vmhbaXX

Where vmk0 andvmk1aretheVMkernelnetworkadapterscompatiblewithiSCSIportbindingrequirements.

YoucangetthelistofVMkernelnetworkadaptersconnectedtoallvSwitchesbyusingthecommand

esxcfg-vmknic -l. vmhbaXX is the sotware iSCSI adapter vmhba ID.

You can veriy the binding details by using the ollowing command:

esxcli iscsi networkportal list --adapter vmhbaXX.

Then rescan the sotware iSCSI adapter to veriy that multiple paths are available or iSCSI LUNs.

3ConfguringPortBindingonvSphere4xUsingCLI

Toenablevmknic-basedmultipathingorsotwareiSCSIruntheollowingCLIcommands- esxcli swiscsi nic add --nic vmk0 --adapter vmhbaXX

- esxcli swiscsi nic add --nic vmk1 --adapter vmhbaXX

Where vmk0 andvmk1aretheVMkernelnetworkadapterscompatiblewithiSCSIportbindingrequirements.

YoucangetthelistofVMkernelnetworkadaptersconnectedtoallvSwitchesbyusingthecommand

esxcfg-vmknic -l. vmhbaXX is the sotware iSCSI adapter vmhba ID.

Ater confguring port binding, you can veriy the binding details by using the ollowing command:

esxcli swiscsi nic list --adapter vmhbaXX.

Then rescan the sotware iSCSI adapter to veriy that multiple paths are available or iSCSI LUNs.

iSCSI Re-loginIyouhaveanalreadyestablishediSCSIsessionbeoreportbindingcongurationyoucanremovetheexisting

iSCSIsessionsandloginagainortheportbindingcongurationtotakeefect

TolisttheexistingiSCSIsessionsruntheollowingcommand

- esxcli iscsi session list --adapter vmhbaXX

ToremoveexistingiSCSIsessionsruntheollowingcommand

- esxcli iscsi session remove --adapter vmhbaXX

ToenablesessionsasperthecurrentiSCSIcongurationruntheollowingcommand

- esxcli iscsi session add --adapter vmhbaXX

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Veriying Multipath Confguration

1VeriyingtheiSCSILUNConfgurationAteryoucompletetheportbindingcongurationandperormtheiSCSIadapterrescanveriythatiSCSILUNs

aredetectedanddisplayedwiththeavailablepathsForexampleiyouhaveboundtwoVMkernelnetwork

adapterstotheiSCSIadapteryouwillseetwopathstoeachLUNconnectedtotheiSCSItargetsToconrm

runtheesxcfg-mpathcommandromCLIorclickthePathstaborLUNsontheGUI

Sampleoutput

Beoreportbindingthereisonepathavailabletoeachtarget(TT)

AterportbindingtwoVMkernelnetworkadapterstotheiSCSIadaptertherearetwopathsavailable

toeachtarget(TT)

2Veriyingvmknic-BasedMultipathFailover

ToidentiytheVMkernelnetworkadaptercurrentlyusedbytheiSCSIadaptertotransmitI/Oruntheesxtop

commandIntheollowingexampleI/Oistransmittedthroughvmk(vmnic)

Toveriyvmknic-basedmultipathailoverdisableanyoneothenetworkadaptersconnectedtotheVMkernel

portgroupusedoriSCSIVeriythatthepathstatusisupdatedcorrectlyandthatthepathsconnectedtothe

ailednetworkadaptercardaremarkedasdead

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IntheesxtopoutputtheailednetworkadapterismarkedasallbackandtheI/Oistranserredusingtheother

VMkernelportgroup

3VeriyingLoadBalancingUsingtheRound-RobinPolicy

AterconguringmultipathailoverorthesotwareiSCSIyoucanbalanceI/Otracbetweenthepathsusing

theround-robinpathpolicy

NOTE: Veriy that the iSCSI array supports the round-robin path policy by contacting the array vendor.

Changethepathselectionpolicy(PSP)oriSCSILUNseitherromthecommandlinebyselectingthe

ManagePathsoptionorbyrunningtheollowingcommand

- esxcli storage nmp satp set -s SATP_NAME -P VMW_PSP_RR

TondtheSATPnameusedtoclaimtheiSCSILUNsruntheollowingcommand

- esxcli storage nmp device list -d naa.600601602af129007d698975a6f2e011

RuntheesxtopcommandtoveriythatI/OisdistributedacrosstheavailablepathsortheiSCSILUN

ToincreaseaggregatedIOperormanceonecanchangeRoundRobinIOOperationLimittoalowervaluerom

deault

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ConclusionConguringvmknic-basedmultipathingorthesotwareiSCSIadapterwillhelpvSphereusersenableailoverat

thepathlevelaswellasbalanceI/Otracbetweenthepaths

About the AuthorSudhishPTisaStafEngineerotheVMwareR&DgroupresponsibleorvalidationostorageonVMware

vSpherereleasesHisareaoexpertiseisvirtualizationwithaocusonvSpherestoragetechnologiesHehas

yearsoindustryexperienceandhasbeenworkingwithVMwareIndiaBangaloresinceDecember

VMwr, i.40HillviewAvenuePaloAltoCA404USATel8-486-Fax60-4-00wwwvmwarecomCopyrightVMware,IncAllrightsreservedThisproductisprotectedbyUSandinternationalcopyrightandintellectualpropertylawsVMwareproductsarecoveredbyoneormorepatentslisted

at http://wwwvmwarecom/go/patents VMware is a registered trademark or trademark o VMware, Inc in the United States and/or other jurisdictions All other marks and names mentioned herein may be