Re: [Nbd] probs with nbd-client 2.9.13 running on centos 5.4 (64bit)

[Wouter Verhelst <w@...112...>]

On Tue, Nov 03, 2009 at 08:04:08PM +0100, Daniel Schwager wrote:
> Hi Wouter,
> 
> we try to install nbd-client on an new, vanilla Centos5.4-64bit
> and got a different behavior on 2 points against a FC9-64bit
> installation:
> 
> a) running without using "-nofork" create TWO processes of  nbd-client:
> 		2953 ?        Ss     0:00 /opt/nbd/usr/sbin/nbd-client
> storage13.dev.xx.de 1024 /dev/nbd0
> 		2954 ?        S      0:00 /opt/nbd/usr/sbin/nbd-client
> storage13.dev.xx.de 1024 /dev/nbd0
> 
>    running the same command on FC9 forks only ONE nbd-client process and
> one nbd0 process:
> 		20655 ?        S      0:00 /opt/nbd/usr/sbin/nbd-client
> storage13.dev.xx.de 1024 /dev/nbd0
> 		20656 ?        S<     0:00 [nbd0]
> 
>    Is this a problem ?

I don't think so, but I'm not sure where the difference is coming from.
I'm guessing that the kernel just doesn't rename the process to a kernel
thread on CentOS, while it does do so on Fedora, but I'm not sure.

Could you mail me (off-list) an strace of both cases, so I can
investigate? Thanks.

> b) Running nbc-client with -c to get the PID fails on centos 
>    because of missing file /sys/block/nbd0/pid:

That's because 2.6.18 was released in October 2006, and the patch that
added that PID file got into Linus' tree in December of that year...

Commit-id (if you wish to cherry-pick the patch) is
6b39bb6548d60b9a18826134b5ccd5c3cef85fe2

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