[OpenAFS] Strange behavior with bonnie++ on AFS

Achim Gsell achim@cybercity.ch
Mon, 22 Nov 2010 17:29:58 +0100


running bonnie++ on OpenAFS with large files (-s 8192) behave strange on =
my Linux systems: after writing up to 7 files with 1GB each, write =
performance drops from 50-60 MB/s to around 3MB/s. At the same time =
OpenAFS client and server start playing ping pong on the network. The =
load on the network is constantly above 50 MB/s when the problem occurs, =
going down to ~35 MB/s after some time - while the "real" transfer is =
still around 3 MB/s. After killing bonnie++ everything is OK again.=20

Tested with 2 clients:
Scientific Linux 5, kernel 2.6.18-194.17.1.el5 and 2.6.18-194.17.4.el5=20=


$ cmdebug localhost 7001 -cache
Chunk files:   4096
Stat caches:   6144
Data caches:   4096
Volume caches: 200
Chunk size:    262144
Cache size:    1048576 kB
Set time:      no
Cache type:    memory

Scientific Linux 5, kernel 2.6.18-194.17.4.el5

Server and clients are test-systems without any other load.

Any ideas?