2.6.0 NFS-server low to 0 performance
Quoted 7 lines · Trond Myklebust
På lau , 10/01/2004 klokka 11:08, skreiv Andi Kleen:
Quoted 6 lines
Quoted 3 lines · Trond Myklebust
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.
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Quoted 2 lines
Please do that. Fragmented UDP with 16bit ipid is just russian roulette at today's network speeds.
I fully agree.
Chuck Lever recently sent an update for the NFS 'mount' utility to Andries. Among other things, that update changes this default. We're still waiting for his comments.
If mount defaults to trying TCP first then UDP if the TCP mount fails, should there be separate options for [rw]size depending on what type of mount actually takes place? e.g. 'ursize' and 'uwsize' for UDP and 'trsize' and 'twsize' for TCP ?
James Pearson
På må , 12/01/2004 klokka 09:40, skreiv James Pearson:
Quoted 4 lines
If mount defaults to trying TCP first then UDP if the TCP mount fails, should there be separate options for [rw]size depending on what type of mount actually takes place? e.g. 'ursize' and 'uwsize' for UDP and 'trsize' and 'twsize' for TCP ?
No. The number of "mount" options is complex enough as it is. I don't see the above as being useful.
If you need the above tweak, you should be able to get round the above problem by first attempting to force the TCP protocol yourself, and then retrying using UDP if it fails.
Changing the default r/wsize should normally be unnecessary. You only want to play with them if you actually see performance problems under testing and find that you are unable to fix the cause of the packets being dropped.
Cheers,
Trond
Quoted 11 lines · Trond Myklebust
P? m? , 12/01/2004 klokka 09:40, skreiv James Pearson:
Quoted 4 lines
If mount defaults to trying TCP first then UDP if the TCP mount fails, should there be separate options for [rw]size depending on what type of mount actually takes place? e.g. 'ursize' and 'uwsize' for UDP and 'trsize' and 'twsize' for TCP ?
No. The number of "mount" options is complex enough as it is. I don't see the above as being useful.
If you need the above tweak, you should be able to get round the above problem by first attempting to force the TCP protocol yourself, and then retrying using UDP if it fails.
I have a patch, sent to the util-linux maintainer, that adds a couple of new mount options to nfsmount. Those allow you to force either of tcp, udp, tcp then udp, and udp then tcp, using the existing proto=xxx syntax. It's available at
http://www.mulix.org/code/patches/util-linux/tcp-udp-mount-ordering-A3.diff
It also cleans up nfsmount() somewhat, although it could certainly do with further rewrite^Wcleanups. I'm waiting to hear from the util-linux maintainer before embarking on that, though.
Cheers,
Muli
Signature · 4 lines
Muli Ben-Yehuda http://www.mulix.org | http://mulix.livejournal.com/ "the nucleus of linux oscillates my world" - gccbot@#offtopic