I would agree about the Raid-5 thing, we had 3 Exim MTA's load balanced each
with 4 disks in Raid 5 and the throughput was terrible. All we did was swap
that for 2 raid-1 disk sets (One for OS, one for mail spools) and we saw a
100 fold increase in performance.
Our machines are now purring along (and we didn't have to use the no-atime
option yet).
-Andy-
> -----Original Message-----
> From: Jaye Mathisen [mailto:mrcpu@mathisen.org]
> Sent: 16 August 2005 19:14
> To: Simon Chappell
> Cc: exim-users@???
> Subject: Re: [exim] HArdware Suggestions for exim courier-imap
>
> Nothing wrong with your config, generally speaking more
> spindles are better.
>
> We ran just a hair under 20k user with qmail and
> courier-imap/pop3 off a dual P3 box.
>
> The key was RAM, fast RAID (stay away from RAID 5 if you can,
> stick with 10 if you can, and spread teh load out.
>
> We used 3ware 12 port 8000 series RAID cards, the new 9000
> cards are even faster.
>
> SO get yourself a good 12 port 3U SATA enclosure, use the WD
> 10k drives, or other good high-memory caching drives, create
> several different arrays to do different parts (storage
> separate from queue separate from OS separate from database),
> and go for it.
>
> There are arguments for and against software vs hardware
> RAID. the 3ware RAID is a no brainer, integrates into
> FreeBSD and linux, has an easy to use console management
> tool, and for us, was rock solid.
>
> Or get a good supermicro box with the adaptec ZCR raid.
>
> Or get 2 lower-end boxes, and a good load balancing switch,
> an have some failover capability as well.
>
>
> On Tue, Aug 16, 2005 at 06:48:46PM +0100, Simon Chappell wrote:
> > Thanks to everyone for the help. It has been interesting getting
> > everones opinions as most of the information about "What to Buy" is
> > pretty non-existant.
> >
> >
> > The things I have noted is if the bean counters give us the
> go ahead
> > for a large lump of money then
> >
> > Branded Server eg HP or even Sun if the budget allows Dual
> Opteron or
> > Dual Core 3Ghz+ 4Gig ram Ultra320 Raid Card 3x 145GB drives Raid5
> > Maildirs
> > 2x 80GB drives Raid1 OS
> >
> >
> > IF not and we have to go cheaper (More likely in the real world)
> >
> > Whitebox
> > Dual Opteron or Dual Core 3Ghz+
> > 4Gig ram
> > 4XSATA 200GB Raid 0+1 Maildir
> > 2xSATA 160GB Raid1 OS
> >
> > Probably about 10 grand gap in between but at least I have a good
> > bearing and should end up somewhere in the gap in the middle.
> >
> > That much processing power should cover us for the
> foreseeable future
> > including expansion and more users over the current 700.
> >
> > Also adding the atime to the fstab may have bought us time to think
> > (or time to put of until it becomes a problem again) and run some
> > tests of our own to help us make the right choice.
> >
> > Thanks Again
> >
> > Simon
> >
> >
> >
> >
> > Mike Meredith wrote:
> >
> > >On Tue, 16 Aug 2005 11:57:06 -0400, Chris Meadors wrote:
> > >
> > >
> > >>I actually prefer the Linux kernel's software RAID over
> controllers
> > >>these days. The data is stored in a non-proprietary on
> disk format,
> > >>so one isn't as the mercy of the controller if something goes
> > >>horribly wrong. I've even found the performance to be
> better than
> > >>the cheaper hardware SCSI RAID cards on the market.
> > >>
> > >>
> > >
> > >Even if the on disk format is documented, I'd still rather recover
> > >from backups. Mind you there's other reasons for not
> liking "intelligent"
> > >controllers (recalling a certain RAID controller on which you were
> > >supposed to run a parity check once a week, which involved
> shutting
> > >down a large Alphaserver and booting off a boot floppy
> with the RAID
> > >controller software on).
> > >
> > >
> > >
> > --
> > ## List details at http://www.exim.org/mailman/listinfo/exim-users
> > ## Exim details at http://www.exim.org/ ## Please use the Wiki with
> > this list - http://www.exim.org/eximwiki/
> >
> >
> > !DSPAM:4302286a99161666570589!
> >
>
>
>
