Re: 2.6.0 NFS-server low to 0 performance

From: Guennadi Liakhovetski (g.liakhovetski_at_gmx.de)
Date: 01/10/04

  • Next message: Peter Osterlund: "Re: Do not use synaptics extensions by default" 
    Date: 	Sat, 10 Jan 2004 21:04:03 +0100 (CET)
To: Trond Myklebust <trond.myklebust@fys.uio.no>

    On Sat, 10 Jan 2004, Trond Myklebust wrote:

    > På 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
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  • Next message: Peter Osterlund: "Re: Do not use synaptics extensions by default"

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