Size of partition.

[Albert Shih]

Le 27/04/2018 à 15:04:40+0200, Eric Luyten a écrit
>
>
> 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,

Very impressif (well...at least for me ;-) )

> 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 activated squatter but put the index not on ssd. The index created by
squatter are (in my case) about 5-8% of the size of the mailbox.

But I got lot of « conversation »  index. What's the purpose of those «
conversations »  ?

> I just checked ... we have 90 GB of cyrus.{cache, header, index}

Ok thanks a log.

>
> SSDs can now be had in capacities of 3.2 TB

Yes, but my boss will kill me if I present to him the price of this SSD ;-)
and I will very guilty if after 5 years only 1 % of this ssd are used ...

Thanks you for you help.

Regards
--
Albert SHIH
DIO bâtiment 15
Observatoire de Paris
xmpp: jas at obspm.fr
Heure local/Local time:
Fri Apr 27 15:42:06 CEST 2018