Ubuntu 10.04;Samba Fast, then slow???

[redmk2]

Mount Command Looks Like

mount -t smbfs //user@server/sharename share

This doesn't look right to me. The basic mount command should look like this

mount -t cifs //server/share mount_point

See

man mount.cifs

Then I used this command to copy

cp -Rpv Documents "Documents backup"

I am using a gigabit Ethernet Intel PWLA8391GT PRO/1000 GT PCI Network Adapter. And I am using Cat5E

Cat5E is marginal at gigabit speeds.

Before coming to this forum, I did try some extra research and did try a couple configuration Changes. Based on an Article by Samba
For Example,I have tried adding this criteria at one point
TCP_NODELAY
SO_KEEPALIVE
IPTOS_LOWDELAY

Adding this criteria did in fact increase the speeds, but then it drops again. I even tried at one point setting the socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
but that actually decreased the speed. I just can't figure out why it will transfer at 34 megs a second for 2 min... and then it drops to 2megs a second for the rest of the time, and then I have to restart my entire system to get the 34 meg speeds again.

You might want to consider monitoring the system with dstat and iperf during the transfer.

I have to agree with @lukeiamyourfather, I don't think Samba (used correctly) is your problem. I have no experience with ESXI so I can't comment on that.

[ian dobson]

Hi,

What does iotop -o -P show when samba is "slow".

I've seen on my backend server (16Gb ram,8 core, 8Tb RAID5 array) that the samba deamon sudenly goes to a very hgh IOWait reading something from the array (even when just writing from another computer).

After a couple of minutes the iowait drops to a "normal" value and the wite speed goes back up to 30-50M/Byte sec.

When transfering large amounts of data (>30Gb) I usually use ftp as that seems to be much quicker than samba.

Regards
Ian Dobson

[Thegmandrive]

Hi,

What does iotop -o -P show when samba is "slow".

I will try that sometime tonight and report back,

You might want to consider monitoring the system with dstat and iperf during the transfer.

I will try dstat, and I will also try to to mount the share as you suggested I will report.

[Thegmandrive]

Well, I was using Samba 3.4, and I decided, since nothing else was working, to try and update to 3.6

I have now tested transferring over 20 gigs, and only saw a few minor drops in speed, but the average stayed around 34 megabytes a second. Woot!! another thing I noticed is that after the transfer, samba now releases unused memory, which i don't think it was doing before.

I am on 10.04 so I did need to compile from source to upgrade to 3.6, so I'm not sure I would suggest this as a "fix" to people seeing as 3.6 is not officially supported by Ubuntu repo's yet.

thanks everyone for your help.