Linux NFS client and FreeBSD server strangeness

Mike Tancsa mike at
Wed Apr 4 20:15:00 UTC 2018

On 4/4/2018 4:04 PM, Kaya Saman wrote:
> I think I posted a similar topic ages ago but got no response. It would
> be interesting to see the cause for this. I have a hunch it could be
> something to do with the nfs implementation of Linux but it is just pure
> conjecture on my side.

I know what you mean about the zfs / zil lockups. It makes a HUGE
difference performance wise if you run with sync disabled on writes for
the zfs dataset. Not sure I want to do that. I am going to try later
with ZIL on some NVE devices and see I can have the best of both worlds.
 I have individual zfs data sets for each server to write their backups
to.  I might be able to live with the risk of running with sync disabled
to receive backup files with.

I think I may have found the setting on the LINUX client.  If I mount
with the options

-o tcp,intr,noatime,sync,vers=3

ie sync

I get the "smooth" traffic patterns. Its actually a bit slower than the
with the default async which I guess is able to burst up higher.

I am not sure how dangerous running async writes are on an nfs client.
But for now, this mystery seems to be a bit better explained to me!


Mike Tancsa, tel +1 519 651 3400 x203
Sentex Communications, mike at
Providing Internet services since 1994
Cambridge, Ontario Canada

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