[Samba] samba 3 - smb2 cpu usage
d.wijsman at stokvis.eu
Mon May 13 09:02:21 MDT 2013
Op 13-5-2013 14:57, Volker Lendecke schreef:
> 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?
Thanks for replying.
'perf top' smb2 enabled shows:
Events: 33K cycles
53.07% [kernel] [k] hypercall_page
36.33% smbd [.] SHA256_Update
1.99% [kernel] [k] copy_user_generic_string
1.23% libc-2.13.so [.] 0x793e1
1.10% [xen_netfront] [k] xennet_poll
'perf top' smb2 disabled shows:
Events: 16K cycles
72.59% [kernel] [k] hypercall_page
12.04% smbd [.] 0x40a5ee
1.86% [kernel] [k] copy_user_generic_string
1.37% [xen_netfront] [k] xennet_poll
0.56% libc-2.13.so [.] 0x89283
0.35% [kernel] [k] xen_restore_fl_direct
0.35% [kernel] [k] pvclock_clocksource_read
Looking at the above, disabling client and server signing gives me (in a
quick test) back my performance.
But now I'm prone to man in middle attacks? and if we run into other
interoperabilities. (e.g. Windows clients/servers)?
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