[OpenAFS] Re: bonnie++ on OpenAFS

Achim Gsell achim.gsell@psi.ch
Mon, 22 Nov 2010 20:01:31 +0100

On Nov 22, 2010, at 7:11 PM, Andrew Deason wrote:

> On Mon, 22 Nov 2010 18:00:41 +0100
> Achim Gsell <achim.gsell@psi.ch> wrote:
>> Hi,
>> bonnie++ on OpenAFS with sizes above 8192 behaves strange on my Linux
>> systems: after writing up to 5-7 files with 1GB each, write
>> performance drops from 50-60 MB/s to around 3MB/s.
> Is this writing to several files sequentially? Or do you mean bonnie++
> writes has about 5-7 files open at the same time, and has written =
> 1G into each?

I mean the latter. If you start bonnie++ with -s 8192 it opens 8 files =
and starts writing sequentially to these files: the first file will be =
filled with 1 GB then the second and so on.

> If the latter (or regardless), I'd try increasing the size
> of the cache; since you're seeing traffic across the network, I'd
> suspect you're thrashing.
Trashing? Mmh. I can write 8 1 GB in parallel with dd without problems =

> If you feel like sharing a network dump of the
> traffic when the problem occurs (probably not to the list), we could
> tell you what it all is.
I will store a network dump in my public AFS directory and tell you as =
soon as I have it - may take some time ...