[Samba] samba 3 - smb2 cpu usage

[Volker Lendecke]

On Mon, May 13, 2013 at 12:52:56PM +0200, Danny wrote:
> Hi all,
> 
> At the moment we are running Debian squeeze with stock samba 3.5.6.
> and are testing some new samba installations from ubuntu 12.04,
> centos 6.4 and debian wheezy. All running in a VM on a XenServer.
> The samba servers are member of a 2008R2 domain, using smb1 protocol
> all are running fine and we get a constant 90MB/s (big file
> transfer) on our 1GB network.
> We would like to enable smb2 protocol for performance reasons, but
> when we do enable SMB2 (max protocol = SMB2) file transfer speed
> drops to 50-60MB/s (one big file) instead of the 80-90MB/s we used
> to get before. We noticed when this happens the cpu is at its max
> instead of 60-70% when using smb1.
> iostat doesn't show any serious load and our raid 10 setup isn't
> experience any difficulties.
> Using the packages (3.6.13) from EnterpriseSamba we get simular results.
> 
> Is it known enabling smb2 requires a faster cpu and our cpu is
> simply not powerfull enough or is there another problem which we
> should look into? (Or should we just stick to smb1, because smb2
> isn't worth the trouble?)

You should definitely use SMB2. The higher CPU is
suprising. You should be able to max out a 1GB network with
SMB2 easily. Does Debian support the perf utility to find
out what the process does?

Volker

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