A quick and easy performance improvement

[Mike Kercher]

I don't suppose this would have any effect if you are using MySQL for
bayes, right?

Mike
 

> -----Original Message-----
> From: mailscanner-bounces at lists.mailscanner.info 
> [mailto:mailscanner-bounces at lists.mailscanner.info] On Behalf 
> Of Richard Lynch
> Sent: Wednesday, July 26, 2006 8:31 AM
> To: MailScanner discussion
> Subject: A quick and easy performance improvement
> 
> 
> I thought I'd post to the list about a change I made 
> yesterday which provided a huge boost in system's performance.
> 
> By far the largest amount of time spent in the life of a disk 
> I/O operation is seek time.  Seek time is the amount of time 
> it takes to move the disk R/W heads from one cylinder to 
> another.  The /var/spool filesystem is where the inbound and 
> outbound mail queues are located.  
> Note also that the Bayes database is accessed heavily when 
> analyzing a message.
> 
> Like many installations we have our root filesystem (/) and 
> /var filesystem on separate partitions on a single hard 
> drive.  The default location for the SpamAssassin bayes 
> database is in /root/.spamassassin/ 
> which is on the rootfs.   Moving the bayes database to 
> /var/spool/spamassassin resulted in a huge decrease in IOWait 
> time.  In our case it was an order of magnitude reduction.  
> For example,  IOWait percentages went from 30% to 3%.  IOWait 
> is the percentage of time the processor is waiting on an I/O 
> operation to complete.  Our mail queues no longer get behind 
> and throughput is outstanding! 
> 
> Making the change is trivial (from root)....
> 
> 1. Shutdown MS
> 2. mkdir /var/spool/spamassassin
> 3. mv .spamassassin/bayes* /var/spool/spamassassin/ 4. Edit 
> /etc/MailScanner/spam.assassin.prefs.conf and uncomment the
>     lines which define where the bayes DB is located.  Thanks 
> Julian!  
> The lines
>     are...
> 
>     auto_whitelist_path        /var/spool/spamassassin/auto-whitelist
>     auto_whitelist_file_mode   0600
>     bayes_path                 /var/spool/spamassassin/bayes
>     bayes_file_mode            0600
> 
> 5. Start MS
> 
> 
> Just wanted to let others know and perhaps benefit from our 
> experiences.
> 
> Richard Lynch
> Morgantown
> 
> -- 
> 
> 
>