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Re: [webmin-l] High I/O usage issues which may be relatedto Usermin...
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From: <ra...@si...> - 2006-10-08 04:49:38
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I have been fighting this problem for some time now, and it always seems to be specific users from specific PC's, and I can never personally reproduce the problem, but just see the results of it's occurance (though I have taken some interesting core files that seem to point to a Perl related issue). However, as I am also using Dovecot for pop/imap, I changed the access to using localhost imap, and the problem seems to have not returned for these users. rf On Fri, 6 Oct 2006, Jamie Cameron wrote: > On 6/Oct/2006 21:25 Jesse C. Smillie wrote .. >> Currently I'm using Sendmail with the mbox format. What you say does >> make sense though. Towards the end of the year I did notice our email >> traffic increasing so it would be only reasonable that the old way of >> doing things could cause us issues with incoming mail on the rise. >> >> Doing a quick search on google I noticed that doing Maildir shouldn't be >> a huge problem with some minor mods to promailrc. However what I don't >> understand is does that mean new mail goes into >> /var/spool/mail/username/<messages here> or would it be >> ~username/mail/inbox/<messages here>? > > Typically, the inbox for Maildir format is ~/Maildir . > You can have mail delivered to this with a line in /etc/procmailrc like > > DEFAULT=$HOME/Maildir/ > >> Lastly, as far as the conversion is usermin cabable of reading two >> different formats at a time? I ask because I wonder can I just convert >> say all the inboxs first, wait to see what it does, and then convert all >> of their personal folders. Or do I need to do both sides of the puzzle >> at the same time? > > Yes, it can read both - you can have the inbox in Maildir format, but > keep other folders in mbox format under users' ~/mail directories. > > - Jamie > >> We currently are using Dovecot for the Pop3 / Imap side of things and it >> appears to be really easy to convert to the different setting. >> >> Thanks Jaime, bTw. >> -Jesse >> >> >> Jamie Cameron wrote: >>> On 6/Oct/2006 12:06 Jesse C. Smillie wrote .. >>> >>>> Hello once again everyone. Since the new school year started we have >>>> been noticing increasingly high I/O usage on our servers. When I run >>>> the top command quite often you will see the WA status swing from really >>>> low up into the 70-80 even 90% range for up to a min and then drop >>>> again. I spend a little time trying to track down the problem and have >>>> noticed the following: >>>> >>>> When I/O is really high I always see the following line in "ps aux | >>>> grep D": >>>> 1229 14619 0.8 0.2 37272 16520 ? D 14:43 0:00 >>>> /usr/local/usermin-1.230/mailbox/delete_mail.cgi >>>> >>>> (Note: User ID is normally not the same one when polled) >>>> >>>> Sometimes I also see the index.cgi file too, but no where near as much >>>> as the above. >>>> >>>> A coworker in our department had made mention that maybe whats happening >>>> has something do with the process that usermin uses to remove mail from >>>> a mailbox when its deleted. Something about compacting the box during >>>> the delete instead of doing it like Thunderbird and waiting to compact >>>> until space can be saved. I guess case being all the reading and >>>> rewriting required to removed the dead message from the box. >>>> >>>> I don't recall having this problem that bad last year. On occassion >>>> when almost everyone was logged in things would get a little screwy, >> but >>>> not like this. >>>> >>>> General information about our config: >>>> Server: >>>> Processors: Dual Opteron 242's >>>> Ram: 6Gig ECC DDR >>>> HDs: 1.2 TB 3ware Raid Array >>>> OS: Slamd 64 10.2b (Slackware more or less) >>>> Kernel: 2.6.18 >>>> Usermin Version: 1.230 (This was happening in the last version too >>>> however. I just upgraded two days ago to see if the problem went away) >>>> >>>> Unfortunately dealing with I/O problems isn't my speciality so I could >>>> be barking up the wrong tree here. Any suggestions would be greatly >>>> appriciated as always... >>>> >>> >>> What format are your mailboxes in? If they are in mbox format (one file >> per >>> user), when Usermin deletes email it will re-write out the entire mail >>> file with the removed emails taken out. As you might expect, this could >> cause >>> substantial disk IO on large mail files.. >>> >>> The solution I used was to switch to Maildir format, in which each email >> is stored >>> in a separate file. Deleting from this format is much quicker.. >>> >>> - Jamie >>> >>> ------------------------------------------------------------------------- >>> Take Surveys. Earn Cash. 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Influence the Future of IT >> Join SourceForge.net's Techsay panel and you'll get the chance to share >> your >> opinions on IT & business topics through brief surveys -- and earn cash >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV >> - >> Forwarded by the Webmin mailing list at web...@li... >> To remove yourself from this list, go to >> http://lists.sourceforge.net/lists/listinfo/webadmin-list > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys -- and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > - > Forwarded by the Webmin mailing list at web...@li... > To remove yourself from this list, go to > http://lists.sourceforge.net/lists/listinfo/webadmin-list > |
