Tag Archives: SAN

In this blog we will learn how to change the Round Robin Path Selection Policy (VMW_PSP_RR) on FC and iSCSI LUNs in a VMware environment to better balance the I/O load across all active storage paths. Modifying the IOPS limitation to 1 will improve performance where an active storage path might have several queued I/Os. In addition, setting the limitation to 1 allows other active storage paths to service I/O requests.  This will have the benefit of reduced latency and increased throughput. ESXi Round Robin PSP supports two types of limits: IOPS limit: The Round Robin PSP defaults to an IOPS limit with a value of 1000. In this default case, a new path is used after 1000 I/O operations are issued. Bytes limit: The bytes limit is an alternative to the IOPS limit. The bytes limit allows for a specified amount of bytes to be transferred before the path…

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The Scope I’m going to setup Fibre Channel storage network to connect ESXi 7 hosts to a TrueNAS Core storage server using a Cisco MDS series switch. I’ve chosen to use Fibre Channel for my VM datastores because of it’s great performance and reliability and the fact that it works so well with VMware ESXi. Fibre Channel will connect the TrueNAS Core storage server (target) and ESXi servers (initiator) over a fabric. In this setup, I’ve got one Cisco MDS DS-C9148-16p-K9 switch, two Dell R720 ESXi 7 servers and one TrueNAS storage server. All of the servers will have QLogic HBAs with link a speed of 8Gbs. I will create 2 logical networks using VSAN’s to replicate having to separate switches. Although the Cisco MDS 9148-16p-K9 switch has 48 Fibre Channel ports, only 16 of them can acquire port a license by default and the remaining ports have to be activated…

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