APLawrence.com -  Resources for Unix and Linux Systems, Bloggers and the self-employed

Mailbox item count issues


2014/12/17

I mentioned Kerio Archiver for user mailboxes the other day and had several customers ask me what effect archiving messages might have on performance. That's a hard question to answer, because performance can be affected by so many things, but there is a way to get an idea.

First of all, realize that this issue affects all mailservers. For example, here is a Technet article recommending limiting key folders to no more than 5,000 messages with Exchange. I'll just quote one paragraph from that page:



Having a large number of items in a folder will mean than operations in that folder will take longer. Operations that depend on the number of items in the folder include adding a new column to the view, sorting on a new column, finds and searches. Many Outlook plug-ins do sorts or searches as they are running, and these requests may overlap with other Outlook MAPI requests, resulting in a poor user experience.

What are key folders? For Kerio, those would be INBOX and Sent Items. For users who refuse to clean Deleted Items, we can add that. The INBOX is of course the most heavily used - every time new email arrives that folder must be updated and every time a user accesses their email it has to be searched and sorted.

You can get an idea of how much of that goes on by turning on Message Store -> Searching and Sorting in your debug log. First, right click in the log itself and select "Messages".

right click and select messages

Then choose "Searching and Sorting" under Message Store.

turning on Searching and Sorting

You'll see messages like this as people log in and out:

Searching and Sorting

That's from my session with only a few hundred messages in my INBOX. Don't forget to turn that debug message off when you have what you need.

Looking at that for your large mailboxes should give you an idea of the workload caused by these. However, I do need to mention that archiving is not the whole solution when mailboxes have been allowed to grow unchecked. The problem is that when large folders are created, deleting messages leaves just as many empty slots which do have to be searched - you'll save on sorting time, but searching will take almost as long.

There is a way to fix that: stop the Kerio server and (using your operating system tools) rename the INBOX to another name. Restart the server and when the user accesses mail, an empty INBOX will be created for them. If you regularly use a tool like the Archiver after that, the mailbox will not have that "empty slot" issue.



Got something to add? Send me email.





(OLDER)    <- More Stuff -> (NEWER)    (NEWEST)   

Printer Friendly Version

-> -> Mailbox item count issues




Increase ad revenue 50-250% with Ezoic


More Articles by

Find me on Google+

© Anthony Lawrence



Kerio Connect Mailserver

Kerio Samepage

Kerio Control Firewall

Have you tried Searching this site?

Unix/Linux/Mac OS X support by phone, email or on-site: Support Rates

This is a Unix/Linux resource website. It contains technical articles about Unix, Linux and general computing related subjects, opinion, news, help files, how-to's, tutorials and more.

Contact us





A Perl script is "correct" if it gets the job done before your boss fires you. (Larry Wall)

Doing linear scans over an associative array is like trying to club someone to death with a loaded Uzi. (Larry Wall)












This post tagged: