[vchkpw] Migration from MySQL to CDB Files
Hi, I have been having problems with resouce utilization with one of my qmail servers, which basically boils down to reaching the concurrencylimit of tcpserver for my pop3 connections (60) and this brings the server to its knees. The only recourse I have left is to reboot, since even console is not responsive. I have checked my logs, and basically, for each pop3 connection, an instance of mysql is generated to check password for a virtual domain user, this generates swapping. The load average shoots up to 300 and I have seen this go as high as 500. The server is running Linux RedHat 7.3 and has 512MB RAM and 1GB SWAP, for about 4000 users in 70 virtual domains. It also runs Apache for qmailadmin. Since there are not that many users per domain, less than 100 average, will CDB Files be a better solution to this problem? Currently running vpopmail 5.3.19 and qmailadmin 1.0.15 -- Jorge Valdes IT Manager Intercom El Salvador [EMAIL PROTECTED]
Re: [vchkpw] Migration from MySQL to CDB Files
On Jun 25, 2004, at 8:53 AM, Jorge Valdes wrote: I have been having problems with resouce utilization with one of my qmail servers, which basically boils down to reaching the concurrencylimit of tcpserver for my pop3 connections (60) and this brings the server to its knees. The only recourse I have left is to reboot, since even console is not responsive. What happens if you set concurrencylimit to 30? Are people checking their email too often? Is the problem that the POP3 users take a long time to download their email (on dialup)? I have checked my logs, and basically, for each pop3 connection, an instance of mysql is generated to check password for a virtual domain user, this generates swapping. The load average shoots up to 300 and I have seen this go as high as 500. Are you sure there isn't something else happening on the machine that pushes the load up? The server is running Linux RedHat 7.3 and has 512MB RAM and 1GB SWAP, for about 4000 users in 70 virtual domains. It also runs Apache for qmailadmin. Since there are not that many users per domain, less than 100 average, will CDB Files be a better solution to this problem? Can this machine work with more memory? You could add another 512M or even 1G of RAM and alleviate the problem. I'm sorry, but I don't know whether switching to CDB will help with your problem. -- Tom Collins - [EMAIL PROTECTED] QmailAdmin: http://qmailadmin.sf.net/ Vpopmail: http://vpopmail.sf.net/ Info on the Sniffter hand-held Network Tester: http://sniffter.com/
Re: [vchkpw] Migration from MySQL to CDB Files
I doubt this is a MySQL problem. We are using MySQL in several environments, including vpopmail. My guess is I don't have as many users as you, since I set my pop3 concurency at 30 with no problems. Are you running qmail-scanner or spamassassin? These added quite a bit of load to my mail server (dual 2.8 Xeons, 2GB RAM) but it still averages at around 0.3 for the 5min average. It will spike if Razor is slow to respond or one of our customers does a blast e-mail to thier client base. You can try and put MySQL on a seperate server and just have vpopmail connect to the external database and see if that solves any load problems. BTW, What versions are you running? On Fri, 25 Jun 2004 09:53:35 -0600, Jorge Valdes [EMAIL PROTECTED] wrote: Hi, I have been having problems with resouce utilization with one of my qmail servers, which basically boils down to reaching the concurrencylimit of tcpserver for my pop3 connections (60) and this brings the server to its knees. The only recourse I have left is to reboot, since even console is not responsive. I have checked my logs, and basically, for each pop3 connection, an instance of mysql is generated to check password for a virtual domain user, this generates swapping. The load average shoots up to 300 and I have seen this go as high as 500. The server is running Linux RedHat 7.3 and has 512MB RAM and 1GB SWAP, for about 4000 users in 70 virtual domains. It also runs Apache for qmailadmin. Since there are not that many users per domain, less than 100 average, will CDB Files be a better solution to this problem? Currently running vpopmail 5.3.19 and qmailadmin 1.0.15 -- Jorge Valdes IT Manager Intercom El Salvador [EMAIL PROTECTED]
Re: [vchkpw] Migration from MySQL to CDB Files
At 10:57 AM 25/06/2004, Greg Kopp wrote: I doubt this is a MySQL problem. We are using MySQL in several environments, including vpopmail. My guess is I don't have as many users as you, since I set my pop3 concurency at 30 with no problems. Are you running qmail-scanner or spamassassin? These added quite a bit of load to my mail server (dual 2.8 Xeons, 2GB RAM) but it still averages at around 0.3 for the 5min average. It will spike if Razor is slow to respond or one of our customers does a blast e-mail to thier client base. You can try and put MySQL on a seperate server and just have vpopmail connect to the external database and see if that solves any load problems. BTW, What versions are you running? I cannot add more RAM to the server.. :( I am running qmail-scanner 1.21, spamassassin 2.63(spamd), clamav 0.70, File::Scan 1.15, also I have patched tcpserver to deny connections if the load average is greater than 12 or more than 5 connections from the same IP address. This alleviated the problem temporarily. I have gathered the following average daily stats: 438 IMAP connections0 Rejects due to load/maxip 28708 POP3 connections 308 Rejects due to load/maxip 7355 SMTP connections 128 Rejects due to load/maxip Bloquing: 10 Emails due to policy reasons 2923 Emails due to Virus 595 Emails due to Spam 15.0 pts. 39.4% spam/ham ratio Each instance of mysql Ver 11.18 Distrib 3.23.58, for pc-linux (i686) uses PID USER PR NI VIRT RES SHR S %CPU %MEM TIME COMMAND 1055 mysql 9 0 14500 9376 1152 S 0.0 1.8 4:28 mysqld So when there are several concurrent POP3 connections, another instance of mysql is spawned to query the DB. I think this is whats bringing the server to its knees... In any case, has anyone done a MySQL to CDB migration? -- Jorge Valdes IT Manager Intercom El Salvador [EMAIL PROTECTED] Tel. 503-278-5068 Tel. 503-265-7070 Fax. 503-265-7025
Re: [vchkpw] Migration from MySQL to CDB Files
On Jun 25, 2004, at 11:54 AM, Jorge Valdes wrote: I am running qmail-scanner 1.21, spamassassin 2.63(spamd), clamav 0.70, File::Scan 1.15, also I have patched tcpserver to deny connections if the load average is greater than 12 or more than 5 connections from the same IP address. This alleviated the problem temporarily. I would replace qmail-scanner 1.21 with qmail-spamc (for SpamAssassin processing) and qscanq (for ClamAV virus filtering). You would eliminate the Perl overhead of Qmail-Scanner and block incoming viruses at the qmail-smtpd level (cuts down on bounce message generation). I have been extremely happy with the results. My knowledge of process accounting is limited, otherwise I'd try to recommend something that could report on how much processor time and swapping was caused by different programs. If you don't have a lot of account adds/deletes/password-changes, then I'd think that going to CDB would be a good solution. You'll cut down on the memory overhead of MySQL connections, and looking up users in the CDB file should have a lower overhead. What's the maximum number of users you have in a domain? -- Tom Collins - [EMAIL PROTECTED] QmailAdmin: http://qmailadmin.sf.net/ Vpopmail: http://vpopmail.sf.net/ Info on the Sniffter hand-held Network Tester: http://sniffter.com/
Re: [vchkpw] Migration from MySQL to CDB Files
On Jun 25, 2004, at 12:26 PM, Rick Macdougall wrote: How are you running both qscanq and qmail-spamc ? I modified qmail-spamc.c to run qmail-queue-real instead of qmail-queue. It's also modified to not run spamc if RELAYCLIENT is set -- this way, mail sent by my users is not scanned. I renamed /var/qmail/bin/qmail-queue to qmail-queue-real. I built qscanq, but I don't think I installed it. I have QMAILQUEUE set in my qmail-smtpd/run script: export QMAILQUEUE='/package/mail/qscanq/command/qscanq' So, qmail-smtpd runs qscanq (since QMAILQUEUE is set), qscanq runs /var/qmail/bin/qmail-queue (which is actually my qmail-spamc) which in turn runs spamc and the real qmail-queue. You can download my modified qmail-spamc.c here: http://tomlogic.com/qmail/qmail-spamc.c -- Tom Collins - [EMAIL PROTECTED] QmailAdmin: http://qmailadmin.sf.net/ Vpopmail: http://vpopmail.sf.net/ Info on the Sniffter hand-held Network Tester: http://sniffter.com/
