On block ISCSI SAN and IOPS |VMware Communities

After chasing the performance gremlins for several weeks, I’ve made some changes and I’m running LiveOptics against my environment and I noticed something particularly interesting that I’m hoping someone can explain to me. 

I don’t expect this to be especially relevant but in the event that it is, here are some details on the environment:
(3) Node Cluster running Essentials Plus with ALL H/A turned off.
(1) EMC VNX 5200 array w/ 32 900GB 10K disks and 9 2TB 7200 disks.
10GB ISCSI Software HBA

(10) Datastores of varying sizes, some with deduplication turned on the array, some on SPA, others on SPB.


Some of my datastores host multiple guests, while others are dedicated to a single guest.  In this particular case, a file server is on node_1 and its’ storage is on VMFS_05.

Reviewing Liveoptic data on IOPS shows expected outputs for node_1.vmfs_05.  But when I look at node_2.vmfs_05 and node_3.vmfs_05, I see something interesting…IOPS where I would expect there to be NONE originating from the nodes that are not hosting the server.  Makes sense?


Is there overhead here that I’m not aware of with ISCSI or maybe between VMWare nodes?  I do see a folder called .VSphere-HA on the datastore as well as .sdd.sf but I have HA turned off currently…so why are nodes that have no business “talking” to VMFS_05, doing I/O against it?


Curiousity more than anything.

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