ESXi v6.x iSCSI multi-path I/O configuration

Tune the iSCSI multi-path I/O settings for ESXi to improve performance. The target is FreeNAS.

Query the devices to get the id of the device to query and modify (if you have multiple devices, consider using xargs):

# DEVICEID=$( esxcli storage nmp device list | egrep "^naa." | head -1 )

# esxcli storage nmp psp roundrobin deviceconfig get -d $DEVICEID
   Byte Limit: 10485760
   Device: naa.6589cfc0000001d94d94727c44f4532a
   IOOperation Limit: 1000
   Limit Type: Default
   Use Active Unoptimized Paths: false

Set the 'IOOperation Limit' (-I <number>) and 'Limit Type' (-t iops):

# esxcli storage nmp psp roundrobin deviceconfig set -d $DEVICEID -t iops -I 1

Verify:

# esxcli storage nmp psp roundrobin deviceconfig get -d $DEVICEID
   Byte Limit: 10485760
   Device: naa.6589cfc0000001d94d94727c44f4532a
   IOOperation Limit: 1
   Limit Type: Iops
   Use Active Unoptimized Paths: false

Notes

Links

• https://forums.freenas.org/index.php?threads/iscsi-multipathing-slower-then-single-path-for-writes.22475/
• http://www.jpaul.me/2011/10/tweaking-vmwares-round-robin-settings/
  
• http://www.gatt-it.co.uk/the-gatt-it-blog/how-to-set-the-round-robin-iops-setting
  
• http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2069356
• http://www.vmware.com/files/pdf/iSCSI_design_deploy.pdf

Appendices

Device List

# esxcli storage nmp device list
t10.ATA_____InnoLite_SATADOM_D150QV_________________20140818AA2041503001
   Device Display Name: Local ATA Disk (t10.ATA_____InnoLite_SATADOM_D150QV_________________20140818AA2041503001)
   Storage Array Type: VMW_SATP_LOCAL
   Storage Array Type Device Config: SATP VMW_SATP_LOCAL does not support device configuration.
   Path Selection Policy: VMW_PSP_FIXED
   Path Selection Policy Device Config: {preferred=vmhba32:C0:T0:L0;current=vmhba32:C0:T0:L0}
   Path Selection Policy Device Custom Config:
   Working Paths: vmhba32:C0:T0:L0
   Is USB: false

naa.6589cfc0000001d94d94727c44f4532a
   Device Display Name: FreeBSD iSCSI Disk (naa.6589cfc0000001d94d94727c44f4532a)
   Storage Array Type: VMW_SATP_ALUA
   Storage Array Type Device Config: {implicit_support=on;explicit_support=off; explicit_allow=on;alua_followover=on; 
      action_OnRetryErrors=off; {TPG_id=1,TPG_state=AO}}
   Path Selection Policy: VMW_PSP_RR
   Path Selection Policy Device Config: {policy=rr,iops=1000,bytes=10485760,useANO=0; lastPathIndex=1: NumIOsPending=0,
      numBytesPending=0}
   Path Selection Policy Device Custom Config:
   Working Paths: vmhba37:C0:T0:L0, vmhba37:C1:T0:L0
   Is USB: false