[Mailman-Users] The Mysterious Disappearing Disk Space (fwd)

[J.A. Terranson]

On Tue, 18 Nov 2008, Mark Sapiro wrote:

> J.A. Terranson wrote:
> >
> >	I have looked through the archives for something similar to my 
> >issue, and I noticed that by searching on "disk full", I get similar 
> >reports beginning in roughly July of 08.
> >
> >	As with these other reports, I have noticed *tremendous* 
> >disappearing space.  When I tried to find the actual files, I was 
> >unsuccessful.  Interestingly, if I stop mailman and then restart it, the 
> >"missing" space miraculously reappears! 
> 
> 
> Is this Solaris? If so, see the thread beginning at
> <http://mail.python.org/pipermail/mailman-users/2008-July/062359.html>
> which is about an alleged memory leak.

FreeBSD 6.3, and the issue in the above thread doesn't look like the same 
thing.

> If you're running out of disk, and restarting the processes solves it,
> it may be swap space that's eating up the disk.

I considered this, however swap is simply not being used at any time.  I 
put up a cron job to monitor, and swap use is literally zero all the way 
up to the crash for lack of space.  Honestly, it *feels* like some huge 
log file somewhere, but I can find no viable explanation for it.  This is 
a single partitioned box, with a single dedicated user (running 4 mailman 
lists and a few websites).  Using du I see space being eaten, but no 
indication as to where.   I see /usr and /var "growing", but looking into 
them shows no file(s) that could account for the amount of missing space.

 
> >	So, now that the background is over with, here's where I find 
> >myself (besides just looking stupid):
> >
> >(1) Yesterday I enabled VERP, and it appeared to be working well,  At the 
> >time I turned on VERP, I had around 5gb of free space (which would take 
> >about two weeks to "disappear" before VERP).
> 
> 
> 5gb of free disk space doesn't seem like a lot these days.

Agreed.  But then, they arent doing much either.

 
> >(2) Around 2pm today, the disk was full, and mailman died.
> 
> 
> Enabling VERP might cause the MTA to use a lot more queue space, but I
> don't see that it would affect Mailman much.

The only difference was in the rate at which the "loss" accrued.  Roughly 
a 6x increase.

 
> >(3) My inkling of something being wrong was this on the web interface:
> >
> >  "Bug in Mailman version 2.1.11rc2
> >
> >  We're sorry, we hit a bug!
> >
> >  Please inform the webmaster for this site of this problem. Printing of 
> >  traceback and other system information has been explicitly inhibited, 
> >  but the webmaster can find this information in the Mailman error logs. "
> >
> >(4) Upon looking at the system in response to the above missive, I checked 
> >and saw the system ws out of space again.  I did what I always do - shut 
> >down mailman (which usually drops ~5gb of "missing" space, and then 
> >restart it.  Everything before today has come up roses doing this.
> 
> 
> So are you saying that this time you didn't recover any disk space or
> just that the web error didn't go away. If the latter, it seems likely
> that the disk space error caused a config.pck file to be corrupted and
> that is the cause of the recurrent "bug". What is the traceback from
> the most recent of these from the error log?

I apologize for the lack of clarity.  Im saying that the space did come 
back, as always, but this time was unique in throwing up this web message.  
All of the mailman core functionality appeared to be running normally 
(lots of traffic back and forth), but the web UI was dead.


> >(5) There is nothing in any of the logs that indicate why this message is 
> >continuing to poke fun at me.
> 
> There almost certainly is something in Mailman's error log unless the
> logfile just can't be grown to accommodate the message.

No, there really isn't.  I have combed through all of them (bounce, error, 
mischeif, post qrunner, smtp & failure, subscribe and vette.  Did I miss 
anything?), with no sign of anything being wrong.  

I have several other mailman systems, and I have always seen a traceback 
or slew of messages when something went south, but nothing here.  Also, of 
note, this is the only mailman with the disappearing disk issue.  My other 
boxen are all running *really* old versions, and this new customer build 
is doubling as my canary:  so far, I see BIG improvements in throughput, 
but this disk thing has me crazy.  If I stop mailman when the drive hits 
99%, I instantly get my 5gb back.  It feels like Im writing a file that I 
cannot see, but I dont think this is physically possible (anyone know 
otherwise?).

I spent a few hours mucking around with the pickles trying to figure what 
broke, and finally gave up due to screaming users: I rebuilt.  The new 
build acts *just* like the last one (the reason for the delay in answering 
your kind reply was to see if the rebuild would get rid of this).  Ive 
lost about a gig over 24 hours, and I have NO idea where its going.  I 
stopped the job while writing this paragraph just to double check, and 
yes, I get it all back when the job is terminated.  Very odd indeed.

Im not comfy with debuggers, so Im at the mercy of others.

Have I missed any log files?  Is there somewhere specific I should be 
looking?  Is there some way to (easily) increase logging details to try 
and track this down?

The answers to this and other important questions await.  On the next 
episode of MailSoap. <cue jingle>
 
Seriously though, I appreciate your response, and the time spent on this.

All the best,

//Alif

-- 
Yours,
J.A. Terranson
sysadmin_at_mfn.org
0xpgp_key_mgmt_is_broken-dont_bother