Hello,
The licensing requirement comes from VMware. MPIO plugins like MEM require either an Enterprise or Enterprise+ license.
PSP is Path Select Policy. NMP, is native multipathing PSA is plugable storage architecture. Vmware designed their storage subsystem to be expandable to suite specific storage vendors. More info about it is here:
Vmware does come with several Path Select Polices.
FIXED, MRU, RR
Fixed means only one path will be used unless there's a failure. Most Recently Used (MRU) is almost identical to FIXED. Except FIXED will always use a specifc path until failure.
RR Round Robin would be what you'd want to use if you can install MEM. For EQL devices we find that the default IOs per path setting needs to be changed. By default it will send 1000 IOs down a path before switching to the next path. Which tends to severely limit the IO potential. We suggest changing that to 3.
This script, will set the default policy for EQL devices to Round Robin and set any EQL volumes to 3 IOPs. As you add volumes or RDMs, you will have to re-run this script on all the nodes. That's another benefit to MEM, new EQL volumes are automatically optimized.
esxcli storage nmp satp set --default-psp=VMW_PSP_RR --satp=VMW_SATP_EQL ; for i in `esxcli storage nmp device list | grep EQLOGIC|awk '{print $7}'|sed 's/(//g'|sed 's/)//g'` ; do esxcli storage nmp device set -d $i --psp=VMW_PSP_RR ; esxcli storage nmp psp roundrobin deviceconfig set -d $i -I 3 -t iops ; done
After you run the script you should verify that the changes took effect.
#esxcli storage nmp device list
Other common settings to check for best performance.
1.) Delayed ACK disabled
2.) Large Receive Offload (LRO) disabled
3.) On VMs with multiple VMDKs or RDMs, create addidtional Virtual SCSI adapters in those VMs.
This blog has some more info about MPIO and delayed ack
Regards,
Don