[Lustre-discuss] Performance drop (1.6.5 vs 1.6.4.3, OFED 1.2)?

[Andrei Maslennikov]

On Wed, Jul 16, 2008 at 4:06 PM, Johann Lombardi <johann at sun.com> wrote:

>
> Does it mean that you run 1.6.4.1 on the OSSs even when testing 1.6.5.1?
> Because 1.6.5.1 clients cannot use adler32 checksums if the OSSs don't
> support
> it and thus fall back to crc32. In 1.6.4.x, checksumming was disabled by
> default
> because crc32 was the only supported checksum type and it hurt performance
> (see
> bug 13805).
>


    Right! This might be an explanation for the great drop in performance in
case
    of tests done with checksumming enabled. (BTW, I always stated that we
have
    1.6.4.1 on servers, but nobody had mentioned so far that there might be
a problem
    on that side...)

    I however worry much more about the case when checksumming is disabled.
Do you
    think that the 20% performance drop may also be explained by the
combination
    of (1.6.4.1 server / 1.6.5.1 client)??

   Andrei.
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