Storage Sizing: IOPS per mailbox

Blake Hudson blake at
Thu Jan 8 10:08:40 EST 2009

-------- Original Message  --------
Subject: Storage Sizing: IOPS per mailbox
From: ram <ram at>
To: info-cyrus <info-cyrus at>
Date: Friday, January 02, 2009 10:40:17 PM
> When sizing a storage device for a large cyrus server, the typical
> question asked by storage vendors is what is the IOPS required per
> mailbox 
> M$$ Exchange has this concept of IOPS. and they suggest 1.5 IOPS per
> mailbox ( heavy users ) 
> If I use postfix and cyrus , on my imap server ( pure IMAP server .. All
> spam filtering , outgoing mails , authentication etc happens on
> different servers )
> If the storage is used only for imap storage , what is the typical
> "IOPS" requirement per user
> We will probably assume 30-50 mails a day of average 100k , and an email
> client checking for new mail every 5minutes 
In my experience I would estimate 0.1 IOPS per user for heavy users
(thousands of emails per day, checked every few minutes) and 0.01 IOPS
per user for typical ISP accounts (under a dozen emails, checked a few
times daily). Our systems use MySQL for authentication and account
verification and primarily skiplist databases within Cyrus. These
figures may be on the safe side as none of our systems do just postfix/imap.


More information about the Info-cyrus mailing list