dovecot - Dec 2010 - Maildir feature I'd like to see - SSD for newer messages

SSD drives are very fast but expensive. So I have a crude idea that I'd 
like to see. May not be practical but would like to get some thoughts on it.

Some new SSDs use SATA 3 (6gb/sec) with 355/mb/sec read speeds and 
215MB/sec write. Put these in raid 0 and it screams! Can you imagine how 
fast that would be?

What would be nice is if new email were on faster drives with old email 
being migrated to larger mechanical cheaper storage. Perhaps messages 
over a month old? From dovecot's perspective it would sort of all look 
the same but maybe one a week a script would run migrating older 
messages to slower media.

It would also make backups easier. The faster newer messages could be 
archived hourly. On the weekend after the archiving script was run the 
older message could be backed up once a week.

I'm not sure what it would take to make dovecot seamlessly access email 
from two different locations or if this is practical. Just wanted to 
throw the idea out there to see if something sticks.

On Thu, 23 Dec 2010 11:27:45 -0800, Marc Perkel <marc at perkel.com> 
 wrote:
> SSD drives are very fast but expensive. So I have a crude idea that
> I'd like to see. May not be practical but would like to get some
> thoughts on it.

 You are asking about automatic storage tiering. You can get what you 
 want in a transparant way, independient
 of Dovecot. Some storage vendor (search for Fully Automated Storage 
 Tiering - FAST from EMC or Compellent, recently
 bought by Dell) get what you are asking for.

 If the budget is low, you can achive a "poor?s man" storage tiering 
 with some shell scripting, cron and soft links; Or you can look at 
 http://code.google.com/p/fscops/ for a more mature implementation. Or 
 just use ZFS and "hybrid storage pools"

 Merry Xmas

 Javier

Quoting Marc Perkel <marc at perkel.com>:
> Some new SSDs use SATA 3 (6gb/sec) with 355/mb/sec read speeds and  
> 215MB/sec write. Put these in raid 0 and it screams! Can you imagine  
> how fast that would be?
I'd never raid-0 anything important...
> What would be nice is if new email were on faster drives with old  
> email being migrated to larger mechanical cheaper storage. Perhaps  
> messages over a month old? From dovecot's perspective it would sort  
> of all look the same but maybe one a week a script would run  
> migrating older messages to slower media.
I used to do something "similar" in that the user's inbox was on
fast
disk, and all their other folders (assumes IMAP for the most part) were
on slower disks.  A cronjob would run once a month that locks the inbox,
selects and mail older than 6 months, and moves it to a folder called
"old-mail" -- thus migrating any 6+ month old mail from fast to slow
storage...

I suppose you could adapt that, maybe with a shorter time period (1 month
would seem okay, not sure about anything shorter).

I know this isn't exactly what you want or asked for, but it is an idea
based on a past implementation which worked well.
> I'm not sure what it would take to make dovecot seamlessly access  
> email from two different locations or if this is practical. Just  
> wanted to throw the idea out there to see if something sticks.
Well, different folders make it a snap...  If you don't want to re-folder,
then it may not be so easy (I'll let someone else answer that).

-- 
Eric Rostetter
The Department of Physics
The University of Texas at Austin

Go Longhorns!