[OpenAFS] poor client performance on linux
Sun, 21 May 2006 12:39:47 +0300 (EEST)
I am using openafs 1.4.1 with linux 188.8.131.52. Afsd runs with
-stat 4000 -dcache 4000 -daemons 6 -volumes 256 -files 50000 -chunksize
The client system serves as an anonymous ftp server, with around
80 ftp server instances concurrently accessing various files on afs. A
particular popular file X is around 2.4 GB large. Other popular files have
sizes starting from 2 Mbytes up to 700.
A test when the afsd has just started with just one ftp
server instance transferring file X achieves speeds 10-20 MB/sec, with
12-15 being the average. Repeated transfers of the same file again with one
ftp client exhibit more or less the same results. Test was made with wget
and lftp. Pure-ftpd is the ftp server software.
When around 80 ftp server instances access afs performance drops
to around 3-60 KB/sec for each one. Load average exceeds 20 and can reach
80. Disk activity is quiet intensive but the system is unable to push
more than 2.5 MB/sec to the network. Killing all ftp server instances and
again testing with only one improves things a bit: speed flactuates between
1-7 MB/sec. Restarting afsd brings performance back to 10+ MB/sec.
I switched the afs cache from one devoted ata100 disk to a 4 disk
ata100 striping raid but nothing changed.
AFS server is p4@ 2.6GHz, 1GB ram 4 sata disks on striping raid.
Its load rarely exceeds 0.5. The ftp server is p4 celeron @ 2GHz, 512MB
ram, afs cache tested on single disk and 4 disk raid. It does not
consume any of its swap at all.All are connected at the same Gigabit
switch. The clients accessing the ftp server are mostly DSL
users and when afs is not involved they usually peek at around
Can anyone think of anything I can do to improve performance?
Best regards ,
Department of Physics @ Aristotle University of Thessaloniki , Greece
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