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Delayed ACK and VMWare Hosts Connecting to Nimble on 10GbE

Question asked by Andrew Wark on Apr 21, 2014
Latest reply on Jul 28, 2014 by Andrew Wark

I was wondering if delayed ack should or should not be disabled in VMWare hosts connecting to Nimble Arrays through 10GbE. I've found some articles regarding this issue and they say to disable it to get the best throughput and latency out of the 10GbE.


Performance = art not science (with DelayedAck 10GbE example) - Virtual Geek


ESX 5.1 iSCSI Bad Read Latency | VMware Communities


From my Nimble to the Host I see very little latency (0-5ms) but the datastores on the Hosts are showing 600-1700ms read latencies and 50ms and under for write latency.


Anyone out there running some form of 10GbE connecting their Nimble array to VMWare hosts and experienced the similar situation?


My situation is we have this one important database server and it's the only server running on this 460 Nimble array (Fig. 1). You can see the differences between the nimble latency view and the veeam one latency view of the virtual machine (fig. 2).


Fig 1. Nimble view of datastores

4-21-2014 2-11-44 PM.jpg


Fig 2. VEEAM One view of latency

4-21-2014 2-13-21 PM.jpg