Adjusting (RR)Round Robin IOPS limit from default 1000 to 10

 260 total views,  2 views today

Leave a Reply

Your email address will not be published.

Adjusting (RR)Round Robin IOPS limit from default 1000 to 10

Adjusting (RR)Round Robin IOPS limit from default 1000 to 10

Adjusting the limit can provide a positive impact to performance and is recommended by some storage vendors to change IOPS limit to 1

The default of 1000 input/output operations per second (IOPS) sends 1000 I/O down each path before switching. If the load is such that a portion of the 1000 IOPS can saturate the bandwidth of the path, the remaining I/O must wait even if the storage array could service the requests. The IOPS or bytes limit can be adjusted downward allowing the path to be switched at a more frequent rate. The adjustment allows the bandwidth of additional paths to be used while the other path is currently saturated.

To verify current iops limit run : esxcli nmp device list

By default is iops=1000

You see output similar to:

Path Selection Policy: VMW_PSP_RR
Path Selection Policy Device Config: {policy=iops,iops=1000,bytes=10485760,useANO=0;lastPathIndex=1: NumIOsPending=0,numBytesPending=0}
Path Selection Policy Device Custom Config:
Working Paths: vmhba33:C1:T4:L0, vmhba33:C0:T4:L0

If you need to change for 10 or different value follow this instruction:

 

Step 1  Add new policy

I included additional thing in Step 1 to make sure that the value is automatically correct for all future LUNs that are assigned.
1. check current policy
esxcli storage nmp satp rule list -s VMW_SATP_ALUA

2. Add new policy (I use IBM SVC storage so I run below)
esxcli storage nmp satp rule add -s “VMW_SATP_ALUA” -V “IBM” -M “2145” -P “VMW_PSP_RR” -O “iops=10”
esxcli storage nmp satp rule add -s “VMW_SATP_ALUA” -V “IBM” -M “2810XIV” -P “VMW_PSP_RR” -O “iops=10”

 

For automation you can use simple script to run on all hosts in your vcenter server

download >> auto_policy_VMW_SATP_ALUA_new

 

 

Step 3 Run PowerCLI to implement new value on each existing datastore, RDM, etc

Single host run:

Get-VMhost esx101.vmlab.local| Get-ScsiLun -LunType Disk | Where-Object {$_.MultipathPolicy -like ‘RoundRobin’} | Set-ScsiLun -CommandsToSwitchPath 10

 

Multiple hosts run:

download >> Lun_iops_changer

 

Please Subscribe

 

 

 

 

 

 758 total views,  2 views today