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Mapping volumes to an ESXi server
31 Dell EMC SC Series: Best Practices with VMware vSphere | 2060-M-BP-V
~ # esxcli storage nmp device set --device=naa.xxx --psp=VMW_PSP_RR
3. Set the IOPS of the device to 3.
~ # esxcli storage nmp psp roundrobin deviceconfig set --device naa.xxx --
type=iops --iops=3
Note: Monitor the vSphere host processor because changing these variables can affect its performance.
To automatically set the IOPS path change condition for all volumes mapped to an ESXi host, the claim rule
can be modified by adding -O "policy=iops;iops=3". For example:
esxcli storage nmp satp rule add -s VMW_SATP_ALUA -V COMPELNT -P VMW_PSP_RR -o
disable_action_OnRetryErrors -e "Dell EMC SC Series Claim Rule" -O
"policy=iops;iops=3"
Caution: This command contains two options that are case-sensitive. The lowercase -o is for the SATP
option string, and an uppercase -O is for the PSP option string.
To remove a previously created claim rule, issue the following command:
esxcli storage nmp satp rule remove -s VMW_SATP_ALUA -V COMPELNT -P VMW_PSP_RR
-o disable_action_OnRetryErrors -e "Dell EMC SC Series Claim Rule" -O
"policy=iops;iops=3"
A reboot is required for this setting to take effect.
For more information and command examples for adjusting these settings, refer to the article, Adjusting
Round Robin IOPS limit from default 1000 to 1 in the VMware Knowledge Base.
6.9.2 Round robin policy for Live Volumes
The Live Volume Asymmetric Logical Unit Access (ALUA) feature was added in SCOS 7.3 and DSM 2018
following the T10 SCSI-3 specification SPC-3 for multiple operating systems. The feature allows the
advertisement of MPIO paths to the primary Live Volume as optimal while MPIO paths to the secondary Live
Volume are non-optimal. When used with the VMware round robin path selection policy (PSP), optimized
paths will be used for read and write I/O when available. Non-optimized paths will be reserved for use in the
event no optimal paths are available. If a Live Volume role swap or automatic failover occurs, the SC Series
array will report the ALUA path state changes to the storage host upon request. The feature allows a round
robin PSP to be used with Live Volume in either uniform or non-uniform storage presentations. The round
robin PSP is easy to deploy, requires minimal administrative effort and documentation, and yields a good
balance of storage port, fabric, and controller utilization.
For more implementation and best-practices information about the Live Volume ALUA feature, see the
document, Dell EMC SC Series: Synchronous Replication and Live Volume.
6.9.3 Fixed policy
While round robin is the recommended policy, if the fixed policy is used, it gives fine-tuned control over the
flow of storage traffic. However, administrators must use caution to evenly distribute the load across all host
HBAs, front-end ports, fabrics, and SC Series controllers.