[OpenAFS] strange disk write activity compared to network bandwidth

Sophana sophana@zizi.ath.cx
Mon, 27 Aug 2007 17:38:28 +0200

Jeffrey Altman a écrit :
> Sophana wrote:
>> Hi
>> I'm evaluating openafs 1.4.4 performance on centos 4
>> I noticed some strange things.
>> I'm doing a simple svn checkout (meaning write to afs) (server on the
>> lan)  of a lot of source files (quite small...) (about 50mbyte+svn
>> overhead ~= 100mbyte)
>> When using gkrellm, I can see the disk write bandwidth at at a high
>> level (> 15mbyte/s), almost no read, and the network bandwidth is MUCH
>> lower (less than 1mbyte/s). It seem that the server is busy making a LOT
>> of disk writes, that are about 10 to 20 times the volume of the real
>> data being written.
> This is only a guess but for every change to a directory the new
> directory contents will be written to disk.  This is in addition to the
> data belonging to the files.
During parallel compilation (10-12 clients...) I also notice a LOT of
writes, almost no read.
How is it possible to cache these writes?
All this is measured on the server of course.