Slow disk write IO with ZFS / NFS

Scott Ullrich sullrich at
Fri Sep 25 19:28:16 UTC 2009


Now that ZFS has been declared "Production ready" I have been playing
around with RC1 + NFS + ZFS.

It seems that write speeds when using ZFS + NFS are pretty poor (on
average 5 megabyte a second).    When I bench the ZFS pool without NFS
I can see up to 175 megabytes a second write speed.

The system in question is a Dell 2850 with 6 ULTRA 300 SCSI 10K RPM
drives (Dual 3.4 ghz XEON) running RC1/AMD64:

FreeBSD 8.0-BETA4 FreeBSD 8.0-BETA4 #2: Fri Sep 25
10:55:46 UTC 2009
sullrich at  amd64

NFS is setup like:


  /vmfs -maproot=root -network -mask 255.255.255.

Does anyone have any pointers on how to speed this up without putting
the data in jeopardy during a power failure, etc (ie: leaving ZIL on).

Thanks in advance,


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