asymmetric NFS transfer rates
Emanuel.Strobl at gmx.net
Tue Nov 2 10:05:21 PST 2004
Am Dienstag, 2. November 2004 17:50 schrieb Andre Guibert de Bruet:
> On Tue, 2 Nov 2004, Emanuel Strobl wrote:
> > Am Dienstag, 2. November 2004 13:47 schrieb Claus Guttesen:
> >>> problems, but I'm wondering why I
> >>> can't write to my 5.3-stable NFS server more that
> >>> 3,5MB/s while reading gives
> >>> me 9,5MB/s?
> >> Are you using IDE- or SCSI-disks? Reading is faster
> >> than writing on IDE.
> > Like I wrote, the server writes more than 35MB/s onto the RAID5 array.
> > Last time I saw a hard drive which has problems with 10MB/s was 6 years
> > ago, no matter of IDE or SCSI.
> You are going by the assumption that the benchmarks are run using
> transfers of a single, contiguous, abnormally huge file. In the real
> world, things aren't that peachy. Remember to factor in things such as
> seek times, drive response latency, driver locking and contention on
> Giant (This is a SCSI RAID card, isn't it?), among other things...
It's a IDE Raid controller (3ware 7506-4, a real one) and the file is indeed
huge, but not abnormally. I have a harddisk video recorder, so I have lots of
700MB files. Also if I copy my photo collection from the server it takes 5
Minutes but copying _to_ the server it takes almost 15 Minutes and the
average file size is 5 MB. Fast Ethernet isn't really suitable for my needs,
but at least the 10MB/s should be reached. I can't imagine I get better
speeds when I upgrade to GbE, (which the important boxes are already, just
not the switch) because NFS in it's current state isn't able to saturate a
100baseTX line, at least in one direction. That's the real anstonishing thing
for me. Why does reading staurate 100BaseTX but writes only a third?
> | Andre Guibert de Bruet | Enterprise Software Consultant >
> | Silicon Landmark, LLC. | http://siliconlandmark.com/ >
> freebsd-current at freebsd.org mailing list
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