[Lustre-discuss] errors on mds and osses regarding to cheksum and decreased stripe counts

[Ender Güler]

Thank you Andreas,
After investigating a little deeper, one of our users' processes creates
lots of smaller files and made i/o. This is the cause of the "fewer stripes"
log message. And for the csum problem my investigation is still in progress.

Thanks again.

On Wed, Jul 1, 2009 at 12:12 AM, Andreas Dilger <adilger at sun.com> wrote:

> On Jun 29, 2009  18:35 +0300, Ender G�ler wrote:
> > We have lustre 1.6.5.1 installation on RHEL 5.1. The interconnect is
> > infiniband. I came across the errors like following, on mds:
> >
> > Lustre: 21241:0:(lov_qos.c:427:qos_shrink_lsm()) using fewer stripes for
> > object 103514695: old 8 new 6
>
> This can happen if some of your OSTs are not responsive to precreate
> requests.  It appears you are using a wide striping by default, which
> is good if you have lots of clients reading/writing from the same file
> on a regular basis, but is not recommended if clients normally read/write
> from a single file OR the bandwidth of a single OST can handle the needs
> of a single client.
>
> > And here is the errors regarding to checksum, on one of the ost's:
> > LustreError: 12397:0:(ost_handler.c:1225:ost_brw_write()) client csum
> > 41d0fa49, original server csum e388fa92, server csum now e388fa92
>
> This looks like you are having network problems, or possibly you are
> using mmap IO?  The data is arriving at the server is different than
> the data that was originally checksummed by the client.  This can happen
> in some cases if the client is doing repeated mmap writes to the same
> part of the file.
>
>
> Cheers, Andreas
> --
> Andreas Dilger
> Sr. Staff Engineer, Lustre Group
> Sun Microsystems of Canada, Inc.
>
>
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