Samba writing speed with big blocks
slitt at troubleshooters.com
Sun Dec 12 21:07:55 GMT 1999
This is just a shot in the dark, but what if you reduce max xmit=? Also,
see what your logs say during the write, and see what tcpdump says during
the write. See what kind of performance FTP has with the big blocks.
At 02:39 AM 12/13/1999 +1100, Petr Sulla wrote:
>I'm having serious problems with Samba's writing speed (both 2.0.5a from
>RH 6.1 and 2.0.6 compiled from sources) on a 100Mbit network.
>If I write a file with block size 65487 or less, then the writing speed is
>7-8 MB/s - a very nice value, my bow to the Samba team :)
>If I change the block size to 65488 or more, then the writing speed falls
>down to 3 MB/s, which is not what I expect from a 100Mbit network :\
>Samba behaves this way even if SO_RCVBUF and SO_SNDBUF are set to 8192
>and "read size" to 16384 and "max xmit" to 16384.
>The corresponding part of my smb.conf looks like this:
> client code page = 852
> preserve case = yes
> socket options = TCP_NODELAY IPTOS_LOWDELAY IPTOS_THROUGHPUT
SO_KEEPALIVE SO_RCVBUF=65535 SO_SNDBUF=65535
> oplocks = True
> getwd cache = Yes
> null passwords = no
> read raw = yes
> write raw = yes
> read size = 65535
> max xmit = 65535
> deadtime = 15
> strict sync = no
> interfaces = 192.168.33.2/24
> remote announce = 192.168.33.255
>The box is a PIII 500Mhz, software RAID5 with read and write throughput of
>and 15MB/s. It has RH6.1 installed, with 2.2.13ac3 kernel. The network card
>uses the DECchip Tulip driver. FTP reads 9MB/s and writes 7MB/s. The tested
>client was W98 SR 1.
>This problem is perhaps not very interesting if you only use Explorer or
>WinCommander, because they both use block size smaller than 65488. But we
>use a special program with greater blocksize... :\
>What causes this strange behaviour ? Is there something strange with the
>2.2.13 kernel, or the ac3 patch ? What could I do about this ?
>Do you experience this too ?
>Please help, because my boss already makes unpolite notices about Linux and
>threatens with installing NT on the server and I would be quite unhappy if
>this would happen.
> Petr Sulla
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