Size of partition.

[Eric Luyten]

On 27/04/2018 14:33, Albert Shih wrote:
> Hi,
>
> Some question about the grow speed of the size of
>
>      /var/imap
>
> because I would put that partition on SSD, and SSD are expensive. I would
> like to know what would be the ratio between the size of mailbox and
> /var/imap.
>
> On my new server I have ~20-25To space for the mailbox. How much /var/imap
> should I get.
>
>

Albert,


We have a Cyrus server with 82,000 users, 500,000 (sub)mailboxes and about
8 Terabyte of mail messages in 9 ZFS filesystems built on an iSCSI SAN 
offering.
Each filesystem holds somewhere between 6 and 11 million messages.

Our /var/imap is 1.5 GB large, it holds the delivery and mailboxes 
databases,
the Sieve scripts, seen information and some local administration stuff.
It has been sitting on the same pair of 73 GB SLC SSDs since August 2010.
The server absorbs between (on average) 80,000 (Saturday) and 250,000 
(Monday)
deliveries per day. At one time we peaked at close to 400,000 deliveries 
in 24 hours,


We're even thinking of, on our next generation, putting all the Cyrus 
metadata
(cache, header, index) on solid state as these represent about 2% of the 
messages
volume (will be more if you have activated delayed expunge and squatter, 
I think).
I just checked ... we have 90 GB of cyrus.{cache, header, index}


SSDs can now be had in capacities of 3.2 TB


Regards,
Eric Luyten, VUB/ULB.