[Samba] Many "smbd" process with "D" uninterruptible sleep status

[Volker Lendecke]

On Thu, Oct 17, 2013 at 03:06:22PM +0800, Simon Wang wrote:
> I got a samba server(Linux) to store some data in my PC(windows)
> frequently.  And last night I found that samba can't work. After logined to
> samba server and found that there's 91 smbd processes with status "D"
> totally.
> # ps
>     169 root         0        SW   [pdflush]
>     170 root         0        DW   [pdflush]
> ....
> 29534 simon  20608 D    /sbin/smbd -D
> 29548 root       2792 D    /bin/sync
> 30160 simon  20608 D    /sbin/smbd -D
> 30474 simon  20608 D    /sbin/smbd -D
> 30496 simon  18676 D    /sbin/smbd -D
> 30673 simon  20504 D    /sbin/smbd -D
> 30810 simon  20504 D    /sbin/smbd -D
> 31302 simon  20608 D    /sbin/smbd -D
> 31965 simon  20608 D    /sbin/smbd -D
> 32288 simon  20608 D    /sbin/smbd -D
> ...
> And after 5 mins the result of "ps" is the same.
> 
> The result of "top" shows below. The load average is VERY HIGHT and CPU is
> busy for io.

Long-running D is almost always a kernel problem. D means
uninterruptible wait. smbd made some syscall that does not
return for a long time. With a working kernel no user space
process should be able to do that. Look at your syslog
(/var/log/messages or /var/log/syslog or such) for kernel
problems. Something else might be extremely slow storage
like a USB1 memory stick. It should eventually come back,
but this could look the same.

Volker

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