Re: [Dovecot] maildir on zfs (was: mailbox format w/ separate headers/data)

2010-01-28 Thread Charles Sprickman


On Jan 22, 2010, at 9:22 PM, Frank Cusack wrote:

On January 22, 2010 9:03:42 PM -0500 Charles Sprickman  
sp...@bway.net wrote:

Sorry for the tangent,


You should probably start a new thread when changing the subject.   
Then

you don't have to be sorry. :)


I figured I was already drifting OT for this list, so...  :)




but I wonder if anyone here is running lots of Maildirs on zfs?


When you say lots of Maildirs I assume you mean filesystem-per-user?
You can of course use lots of Maildirs yet have only a single zfs
filesystem but that doesn't seem to me to be worth questioning.


No, I just meant a large number of users using Maildir (rather than  
mbox, dbox,
whatever else) on a single ZFS filesystem.  Although filesystem per  
user is
an interesting idea.  When my personal box gets upgraded to FBSD 8.0,  
I may

try that for fun.



I am running that way but it's less than 100 users so probably not  
what

you would consider lots.


I'd seen some comments here in the past that zfs+maildirs = bad.


I can't imagine why that would be the case.  There are some problem
loads for zfs (zfs-backed NFS writes, e.g.) but why maildir would be
particularly singled out I wouldn't know.


I think this is the message that got stuck in my head:

http://www.mail-archive.com/dovecot@dovecot.org/msg25478.html

I *think* that when I was doing my massive week-long google binge on zfs
I read a few comments about zfs being non-optimal for email.  It's  
teh

internets though, and it could have been someone just talking out their
behind or it could be talking about a much earlier release of ZFS.

I have a small backups box that's got just 4 WD RE3 drives on it.  The
benchmarks for this thing pretty much blew me away.  We're not talking
top of the line hardware here and it was performing at least as well  
as a

good Areca or 3Ware hardware RAID setup.

Anyhow, if I find more places to run ZFS in production and it seems  
stable
enough, I'd like to try getting it running on my big mailserver at  
some point.
Backing up from UFS to ZFS using rsync is fine, but ZFS send/recv  
looks like

a far more interesting backup solution.

Charles



For filesystem-per-user, if by lots you mean 1000 or 1000s then you
have the problem that it takes forever to mount all of those  
filesytems

on reboot.  That's not a maildir-specific problem though.

-frank



Charles Sprickman
NetEng/SysAdmin
Bway.net - New York's Best Internet - www.bway.net
sp...@bway.net - 212.655.9344



Re: [Dovecot] maildir on zfs (was: mailbox format w/ separate headers/data)

2010-01-22 Thread Dave McGuire

On Jan 22, 2010, at 9:22 PM, Frank Cusack wrote:

but I wonder if anyone here is running lots of Maildirs on zfs?


When you say lots of Maildirs I assume you mean filesystem-per-user?
You can of course use lots of Maildirs yet have only a single zfs
filesystem but that doesn't seem to me to be worth questioning.

I am running that way but it's less than 100 users so probably not  
what

you would consider lots.


  I'm in the same usage range for my ZFS-backed mail server.


I'd seen some comments here in the past that zfs+maildirs = bad.


I can't imagine why that would be the case.  There are some problem
loads for zfs (zfs-backed NFS writes, e.g.) but why maildir would be
particularly singled out I wouldn't know.


  I'm doing everything on ZFS now (database loads, web services,  
etc) and will never go back to UFS. (or ext3, etc)  Zero problems,  
with anything, ever.



For filesystem-per-user, if by lots you mean 1000 or 1000s then you
have the problem that it takes forever to mount all of those  
filesytems

on reboot.  That's not a maildir-specific problem though.


  I'm running filesystem-per-domain; I've found that's a good way to  
do it for my situation.


 -Dave

--
Dave McGuire
Port Charlotte, FL