On 9/23/2010 9:47 PM, Patrick Cable wrote:
> I have a device that sends out information at 4.7 Megabytes a second.
> I have a desktop that receives the data from this device that runs Red
> Hat Enterprise Linux 5.5. They are on the same switch, a 24-port
> Juniper EX2200.
>
> When I write the data to the desktop on the local filesystem, there's
> no dropped information. When I write the data to an NFS share, the
> device reports dropped packets.
>
> I have tried playing with the rsize/wsize NFS parameters (8192K seems
> to be the best value), and values in
> /proc/sys/net/core/{r,w}mem_{default,max} and increasing the NFS
> daemon count, as suggested by
> http://nfs.sourceforge.net/nfs-howto/ar01s05.html. Very similar
> results across the board.
>
> The NFS server also runs RHEL5.5. It's got 11 600gb 15k SAS drives in
> a hardware RAID6 array. Running 'iftop' on the machine during the data
> gathering operations, I'll see bursty traffic... that is to say,
> workstation -> NFS server traffic will be in the high 40mb/sec rate,
> then slow down, and once it slows down the device I refer to complains
> of dropped information then it'll speed up again.
>
> I find it hard to believe that a machine on the same (recent, gigabit)
> switch can't write out 4.7MB/sec. Am I wrong?
>
> Does anyone have any NFS or TCP tuning recommendations that may be a
> little more up to date than the NFS howto that was last updated in
> 2006? I'm really at a loss here.
>
> Thank you, more than a lot, in advance..
What size chunks is the application writing? How many files? What size
files? What is the back-end filesystem behind NFS?
Have you tried simulating the same load directly on the server?
_______________________________________________
Tech mailing list
Tech@lopsa.org
http://lopsa.org/cgi-bin/mailman/listinfo/tech
This list provided by the League of Professional System Administrators
http://lopsa.org/
