[Samba] Am I getting the best performance?

Me aragonx at dcsnow.com
Fri Mar 14 19:26:27 GMT 2003

> On Fri, 14 Mar 2003, aragonx wrote:
>> /sbin/hdparm -Tt /dev/hdd
>> /dev/hdd:
>>  Timing buffer-cache reads:   128 MB in  0.95 seconds =134.74 MB/sec
>> Timing buffered disk reads:  64 MB in  2.43 seconds = 26.34 MB/sec
> This appears to be measuring cache performance - not disk I/O
> performance. Check the drive specifications. Probably more like 35MB/sec
> sustainable write rate.

>From what I understand the first line is cache performance and the second
line is sustained disk performance.

>> /etc/samba/smb.conf
>> SO_RCVBUF=8192 SO_SNDBUF=8192
> Did you check the impact of increasinf the SO_RECVBUF and SO_SNDBUF to
> 128KByte?

No I have not.  I will try it though.  I have 512MB of RAM in my server so
I'm not too worried about memory.

>> I'm running Redhat 8.0 using a custom built 2.4.20 kernel.  The drive
>> referenced above is a Seagate 7200rpm UDMA-33 IDE hard drive.
>> I did a 2GB copy from
>> Linux to a Windows98SE machine using Samba.  I got 5.85MB/sec.
>> I did the same copy on a Windows XP machine and got 6.99MB/sec.
>> Then I copied from hdd to hdc and got 6.94MB/sec. (same channel)
>> Then I copied from hdd to hdb and got 9.30MB/sec. (different channel)
>> It seems to me that I should be able to get close to the 9.30MB/sec
>> when transfering over the network.
>> Still 9.3MB/sec is no where near the 26MB/sec hdparm is reporting...
>> I'm on a 100Mb switch and I'm using 3Com 905TX NICs in both the
>> workstation and the server.
> An 100MB/s == 11 megabytes/sec at peak I/O and no network contention.
> Copared with that 9.3 megabytes/sec is VERY good!

Yes but the 9.3MB/sec was from drive to drive not over the network.

>> I guess the best my network can put out is 12MB/sec.  I was hoping to
>> get around 10MB/sec with Samba.  Is this unreasonable???
> No - not reasonable. You have IP stack, a TCP stack, then buffering from
> the kernel to samba's smbd with is user space, then I/O back to the
> kernel and ultimately to the Disk subsystem. Lot's of overhead in other
> words.
> You did well over 100Mbit ethernet!

Humm.  I can get 10MB/sec using FTP.  Does Samba have more overhead?  I
was told it should perform on par with FTP.  Is this not true?

> What file system? ext2, ext3, reiserfs, xfs, jfs???? Even that makes a
> hugh difference.

All my server file systems are ext3.

Thank you for your reply.

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