Poor SMB performance

M

m1abram

2[H]4U
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Mar 15, 2002
Messages
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Ok so background on setup first. I have an all-in-one ESXi setup using ZFS for a SAN as a guest machine. I have 2 Server 2012 guest machines on the host.(each with 2 vmnx3 nics with RSS enabled)

I wanted to play with SMB3 and multipath and see how it works. So I created a COMSTAR iSCSI volume to mount on one of the Server 2012 VMs then I shared that mount point within the guest. (Yes I know there is overhead and I could share the drive directly from ZFS but then that does not support SMB3)

To get a baseline performance of the iSCSI volume within that VM guest I ran crystalmark and get ~400MB/s seq. read and ~340MB/s seq. write. About what I would expect.

Where this goes bad is from the other Server 2012 guest I only get ~80MB/s seq read and ~90MB/s seq write.

I have confirmed that RSS is enabled on both machines and that it is using the multiple connections. But heck I am not even seeing performance that I would expect from non-multipath let alone multipath.

NOTE since these tests are done within the VM it eliminates and switch or wiring issues and ESXi with vmxnet3 drivers should get really good network speeds between guests.

Any ideas? Thanks
 
Did you search the forum before posting?

I think this question or one very similar was answered the night before you posted this.

After you've made the changes suggested, post here again and let us all know if that did or did not resolve the issue for you.
 
My searching must be very poor. Best thread I could find was this one:
http://hardforum.com/showthread.php?t=1819178&highlight=smb

It did not provide much as far as things to try.

I have improved performance a bit by adjusting the
TCPIP paramater
GlobalMaxTcpWindowSize to 0xffff

LANMANSERVER paramaters
SizeReqBuf to 0x8000
MaxMpxCt to 0x2000
MaxWorkItems to 0x8000

These changes increased the throughput of my SMB transfers between VM guests to ~190MB/s for reads and writes.

I tested my performance from a external (not a vm) machine that has 2 gbit nics connected running windows 8.1. The read and write performance was ~140MB/s which was up from the read/write perfomance to the CIFS share directly on the ZFS server that is providing the storage which was ~110MB/s which is bascially saturation of a single gbit nic. So I do see a performance boost from sharing the storage directly from ZFS to sharing from ZFS to Server 2012 then out.
 
One of the two 2012 servers probably has poor SMB performance, once you identify which one is that...start turning off packet offloading features in the network driver on that machine..
 
Mackintire said:
One of the two 2012 servers probably has poor SMB performance, once you identify which one is that...start turning off packet offloading features in the network driver on that machine..
Click to expand...

Both 2012 machines are VM guests that are clones so that probably is not the issue.
 
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