Re: [Nbd] nbd hanging doing an svnadmin hotcopy

[Eric Gerlach <egerlach@...135...>]

Okay, I have learned another way to find out what the process is waiting 
on, namely getting ps to output the WCHAN field using the -o option. 
Now that I've done that, I see kjournald is hung on sync_buffer, and 
svnadmin is hung on sync_page.

Is there any known problems with using nbd with journaled filesystems?

Sorry for cluttering up the list like this, but I figure if I post 
everything i know, maybe that will help someone else in the future.

Cheers,

Eric

Eric Gerlach wrote:
> About an hour and a half after it froze it started going again, but then 
> froze on the next repository (it's a batch job that backs up all the 
> repositories), and has been frozen for the last six hours or so.  Now 
> svnadmin is stuck in a different place, though nbd-client seems to be in 
> roughly the same place....
>
> Again, if there's anyone out there who can offer a pointer (or where 
> more pertinent data could be found), it would be much appreciated.
>
> Eric Gerlach wrote:
> > Hi,
> >
> > I'm testing out using nbd to host svn repositories because nfs doesn't 
> > work.  However, when tyring to do an svnadmin hotcopy the whole thing 
> > has hung.  I can't even kill -9 the processes involved, so I'm assuming 
> > it's in the kernel.
> >
> > I thought it might be a TCP timeout issue, so I've waited long past the 
> > 15 minute TCP timeout (read that somewhere), but not one bit has changed 
> > in the call traces of the processes during that time.
> >
> > It's a Debian Etch system, running the latest (2.6.18-5) kernel with 
> > nbd-client 2.8.7 userland.  I've pulled the call traces of the offending 
> > process if that helps anyone.  If I'm asking for help in the wrong 
> > place, let me know so I can try there.  However if anyone has any 
> > experience with this, it would be greatly appreciated.
> >
> > Thanks very much in advance for your help.
> >
> > Cheers,
> >
> > Eric

--
Eric Gerlach, Network Administrator
Federation of Students
University of Waterloo
p: (519) 888-4567 x36329
e: egerlach@...135...