2002-08-13 16:52:51

by Brasseur Valéry

[permalink] [raw]
Subject: RE: nfs unlink perf !

> -----Original Message-----
> From: Lever, Charles [mailto:[email protected]]
> Sent: Tuesday, August 13, 2002 6:21 PM
> To: 'Brasseur Val=E9ry'
> Cc: [email protected]
> Subject: RE: [NFS] nfs unlink perf !
>=20
>=20
> hi brasseur-
>=20
> > I check nfsstat, and see a bunch of retrans...
> > but now when then following your suggestion I 've try to put :
> > tcp + rsize/wsize=3D32768 and :
> > * take the same time
> > * hang on D state under moderate load so I need to reboot=20
> > very frequently.
>=20
> if "nfsstat -c" shows lots of retransmissions and you are using
> NFS over UDP, follow these instructions to increase the transport
> socket buffer size:
>=20
> 1. Become root on your client
> 2. cd into /proc/sys/net/core
> 3. echo 262143 > rmem_max
> 4. echo 262143 > wmem_max
> 5. echo 262143 > rmem_default
> 6. echo 262143 > wmem_default
> 7. Remount your NFS file systems on the client
>=20

already done that ! it's my default config !

> if that doesn't clear your problem, then you probably have a faulty
> network -- swap your cabling, look for NIC errors on your client
> and filer, check the statistics on your switch, and be sure duplex
> and autonegotiation are correctly set. you can ask your NetApp SE
> for help diagnosing network problems on the filer if you need it.

no errors are reported by NICs nor switch ! full-duplex is force=20
on all devices (client,filer,switches ...)

>=20
> also try testing from other clients on other networks, if you can.
>=20
> > my previous setup was :
> > * nfs v3, rsize/wsize=3D8192, udp
> >=20
> > my client (DL360) and server (F880) are connected through=20
> a dedicated
> > switch each with 100FD network link to the switch.
> >=20
> > any ideas ?
>=20
> if the above suggestions don't help, get a packet trace. you can use
> "tcpdump" on your client, or you can try "pktt" on the filer.
> ("pktt list" on the filer's console should tell you what you need to
> know). pktt produces a trace file in tcpdump format, so you can use
> tcpdump on your clients to look at the dump.
>=20
> send me the dump if you'd like help.
>=20
> > > -----Original Message-----
> > > From: Lever, Charles [mailto:[email protected]]
> > > Sent: Monday, August 12, 2002 5:48 PM
> > > To: 'Brasseur Val=E9ry'; [email protected]
> > > Subject: RE: [NFS] nfs unlink perf !
> > >=20
> > >=20
> > > link RPCs can be very large (much larger than wsize, for=20
> instance).
> > > if you use UDP and your network drops lots of packets, large link
> > > requests will probably require several retransmissions to=20
> complete.
> > >=20
> > > enlarge your transport socket buffer size on the client (see FAQ)
> > > and/or try NFS over TCP. also examine your network to see if it
> > > is clean, and is working optimally. if your client is attached
> > > via a more slow link than your server, that can be the source of
> > > bursty packet loss.
> > >=20
> > > > -----Original Message-----
> > > > From: Brasseur Val=E9ry [mailto:[email protected]]
> > > > Sent: Monday, August 12, 2002 8:09 AM
> > > > To: [email protected]
> > > > Subject: [NFS] nfs unlink perf !
> > > >=20
> > > >=20
> > > > I am testing an application which to a lot of link/unlink
> > > >=20
> > > > server is a NetApp filer, client is linux 2.4.19+nfs patches.
> > > >=20
> > > > under load it seems that the unlink call is very long when=20
> > > > all over calls
> > > > response time seems to be OK.
> > > > is there any problems with the unlink code ?
> > > >=20
> > > > thanks
> > > >=20
> > > >=20
> > > >=20
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> > > > _______________________________________________
> > > > NFS maillist - [email protected]
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> > > >=20
> > >=20
> >=20
>=20


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