Re: 2.6.0 NFS-server low to 0 performance

[Guennadi Liakhovetski]

On Sat, 10 Jan 2004, Trond Myklebust wrote:

> PЕ lau , 10/01/2004 klokka 06:10, skreiv Guennadi Liakhovetski:
> > Yes. The reason for the problem seems to be the increased default size of
> > the transfer unit of NFS from 2.4 to 2.6. 8K under 2.4 was still ok, 16K
> > is too much - only the first 5 fragments pass fine, then data starts to
> > get lost. If it is a hardware limitation (not all platforms can manage
> > 16K), it should be probably set back to 8K. If the reason is that some
> > buffer size was not increased correspondingly, then this should be done.
>
> No! People who have problems with the support for large rsize/wsize
> under UDP due to lost fragments can
>
>   a) Reduce r/wsize themselves using mount
>   b) Use TCP instead
>
> The correct solution to this problem is (b). I.e. we convert mount to
> use TCP as the default if it is available. That is consistent with what
> all other modern implementations do.
>
> Changing a hard maximum on the server in order to fit the lowest common
> denominator client is simply wrong.

Not change - keep (from 2.4). You see, the problem might be - somebody
updates the NFS-server from 2.4 to 2.6 and then suddenly some clients fail
to work with it. Seems a non-obvious fact, that after upgrading the server
clients' configuration might have to be changed. At the very least this
must be documented in Kconfig.

Thanks
Guennadi
---
Guennadi Liakhovetski


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/