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  • 1.  svmotion from 10G SAN to another 10G SAN, slow

    Posted May 16, 2016 02:53 PM

    Hi

    I have a question.

    I'm migrating VM's from an old badly configured cluster/storage to a new cluster/storage using svmotion.

    My old `gateway` host has 10Gbe connections to both old SAN and new SAN (both Equallogics). When I svmotion from old datastore to new, I'm getting a 1Gbe speed (130MB/s) - its constant as if there's some throttling going on. I don't understand why is not going faster as both SANs have plenty of free IO's so I don't see any bottlenecks there.

    Is there some hard limit to stop saturation that I don't know about?

    Thanks

    Mark



  • 2.  RE: svmotion from 10G SAN to another 10G SAN, slow

    Posted May 20, 2016 02:49 PM

    Hi there,

    This could be the write speed on the target disks that is holding things up as the data will only move as fast as it can be written.

    It also depends on what data mover is being used to handle the transfer, best case scenario FS3DM will be used but various factors could mean that the legacy DM could be in use, check Duncan's blog post to see if you can figure out which mover would be in use.

    Hope this helps



  • 3.  RE: svmotion from 10G SAN to another 10G SAN, slow

    Posted May 23, 2016 03:19 PM

    Hi

    Well its going to and from different physical SAN's so any HW offload will be disabled I guess. Block sizes and VMFS versions are the same though.  Its just strange that its limited to 1Gbps as if there's a hard limit set somewhere.

    I can run an IOmeter from inside a VM to this datastore and I see over 800MB/s write, so I know the disks aren't a problem.

    Thanks