Re: [9fans] upas locking
On Thu Apr 18 12:10:28 EDT 2013, n...@lsub.org wrote: > yes, except that the whole thing > got worse because one of our servers > had a lot of memory used due to > those and we put back the bind for > tmp. ramfs -l 10m (the 9atom version of ramfs does proper accounting to make this work.) also, if you're using anything like mdir, you can deliver the mail and delete it automaticly later. - erik
Re: [9fans] upas locking
yes, except that the whole thing got worse because one of our servers had a lot of memory used due to those and we put back the bind for tmp. On Apr 18, 2013, at 5:33 PM, Charles Forsyth wrote: > > On 18 April 2013 15:51, Fco. J. Ballesteros wrote: >> if one has one problem, it can lock everyone else using /mail/tmp. > > I use a private ramfs, which is also faster.
Re: [9fans] upas locking
> On 18 April 2013 15:51, Fco. J. Ballesteros wrote: > >> if one has one problem, it can lock everyone else using /mail/tmp. > > > I use a private ramfs, which is also faster. Obvious, when one points it out! ++L
Re: [9fans] upas locking
On 18 April 2013 15:51, Fco. J. Ballesteros wrote: > if one has one problem, it can lock everyone else using /mail/tmp. I use a private ramfs, which is also faster.
Re: [9fans] upas locking
Yes, perhaps we should stop using that. Nevertheless, the problem I was trying to address is that everyone is sharing /mail/tmp (see the scripts in /mail/lib, although I'm sure you know them from memory :) ), and thus if one has one problem, it can lock everyone else using /mail/tmp. I'll take a look now to the countermeasures you suggest. I think we are applying a few other measures, including validatesender, but I'll take a look.--- Begin Message --- > The problem was that we had quite a number of upas/fs's and scanmails > running and it was because one of them had a problem and kept a > /mail/tmp/L.mbox file locked. All other ones kept waiting for that > (although all of them were using different "mboxes" created by the > piped script at /mail/tmp/$pid.blah.blah > i'm confused. doesn't this just make the problem smaller rather than fixing it? i would think if scanmail has the same issue, then mail will still go undelivered, right? we don't run scanmail. since scanmail relies on building rules, it needs constant maintence. and i didn't want to be on the hook for that. instead, i use mechanical defensive measures in smtpd and validatesender. the most effective measure is enforcing the rfc2821 rule that the ehlo string must look up in dns. to appease imap4 clients, there's a flag to force auth for clients ehlo'ing incorrectly. spamhaus does a good job cleaning up what remains. - erik http://www.quanstro.net/magic/man2html/8/smtp (yes, that's ugly!)--- End Message ---
Re: [9fans] upas locking
> The problem was that we had quite a number of upas/fs's and scanmails > running and it was because one of them had a problem and kept a > /mail/tmp/L.mbox file locked. All other ones kept waiting for that > (although all of them were using different "mboxes" created by the > piped script at /mail/tmp/$pid.blah.blah > i'm confused. doesn't this just make the problem smaller rather than fixing it? i would think if scanmail has the same issue, then mail will still go undelivered, right? we don't run scanmail. since scanmail relies on building rules, it needs constant maintence. and i didn't want to be on the hook for that. instead, i use mechanical defensive measures in smtpd and validatesender. the most effective measure is enforcing the rfc2821 rule that the ehlo string must look up in dns. to appease imap4 clients, there's a flag to force auth for clients ehlo'ing incorrectly. spamhaus does a good job cleaning up what remains. - erik http://www.quanstro.net/magic/man2html/8/smtp (yes, that's ugly!)
Re: [9fans] upas locking
Yes, I noticed the comment, but I thought it was wrong. The problem was that we had quite a number of upas/fs's and scanmails running and it was because one of them had a problem and kept a /mail/tmp/L.mbox file locked. All other ones kept waiting for that (although all of them were using different "mboxes" created by the piped script at /mail/tmp/$pid.blah.blah Making this change made problems go away, and I didn't notice any problem in imap so far. I guess I'll have to reread the imap source to see if it really requires one lock per dir instead of one per mbox, but even so, I think imap should use a different lock for that, it's upas/fs the one I'm talking about. thanks for the hint On Apr 18, 2013, at 4:04 PM, erik quanstrom wrote: > i think the comment above the function is important > "we use one lock per directory". it's been a long time since > i worked on nupas, so i don't recall all the details, but > iirc, imap4d relies on having one lock per directory.
Re: [9fans] upas locking
> Looking into, we found that in upas/common/libsys.c the > function generating the lock file name returns always "L.mbox" > but not .../L. as it seems it should. i think the comment above the function is important "we use one lock per directory". it's been a long time since i worked on nupas, so i don't recall all the details, but iirc, imap4d relies on having one lock per directory. of course, nupas takes pressure off the directory lock by using mdir format, which doesn't require a lock. the indicies are lock files themselves. under what circumstaces did you find a problem? - erik
[9fans] upas locking
Hi, we found recently that we had a problem with /mail/tmp/L.mbox used by upasfs to lock. Looking into, we found that in upas/common/libsys.c the function generating the lock file name returns always "L.mbox" but not .../L. as it seems it should. Also, the function doing the actual lock hides the error string. I copied our changed file to /n/sources/contrib/nemo/libsys.c Didn't create a patch yet because I'm not sure it's the right change for this problem.
