 | | | NFS Help! Terrible performance with sync, fast performance with async | NFS Help! Terrible performance with sync, fast performance with async 2006-11-20 - By Stephen John Smoogen
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On 11/20/06, Christopher McCrory <chrismcc@(protected)> wrote:
> Hello...
>
> On Sun, November 19, 2006 1:58 am, Chris Wornell wrote:
> > I've got a problem that I've spent quite a bit of time on, though I'm
> > not an expert at NFS. In summary, operations that require meta-data
> > changes (such as file/directory creations/deletions), perform extremely
> > slow over sync, but over 10x faster using async.
> >
>
> The same thing happens with RHEL4; software raid and lvm/lvm2 make it worse.
> I opened a support ticket with RH, but it didn't really go anywhere.
> I'm considering switching my NFS server to FreeBSD 6.2
I am going to assume that you did this a couple of days ago.. as
opening a ticket on a Sunday nigth and expecting a resolution by
Monday morning is a bit tight. If you are more comfortable with
FreeBSD then I would suggest it as you would know how to tune it
better.
To answer your earlier question, I have found that going to TCP on
links faster than 100mb always gives better performance than UDP...
even with crossover cables. I tested this with:
Netapp Server -> AIX 5.3
Netapp Server -> Solaris 2.8/2.9
Netapp Server -> Linux 2.4.20+
Netapp Server -> Linux 2.6.9+
Also a test with Solaris <-> Solaris. The UDP packets only seem to
work ok with jumbo packets on a smart switch that could optimize data
transfers.
File creation is going to always be faster with async... sometimes by
a factor of 10. You can improve your other performance with a Linux
NFS server, you need to be judicious in the network card (I like the
e1000 over the broadcom which has always had weird latencies for me),
and your kernel tuning. The Linux kernel is not set up to be an NFS
server by default and you need to set up the size of the buffers and
network tuning to meet your needs.
The problems sound like more about writing to disk. What does the
local bonnie say when writing to RHEL-4 (See http://HEL-4.ora-code.com) disks? and which version of
RHEL-4 (See http://HEL-4.ora-code.com)?
--
Stephen J Smoogen. -- CSIRT/Linux System Administrator
How far that little candle throws his beams! So shines a good deed
in a naughty world. = Shakespeare. "The Merchant of Venice"
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