Re: Hardware Recommendations
- From: Jonathan Norris <JonathanNorris@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 12 Jan 2006 13:20:02 -0800
I am using a calculator developed by Exchange Rangers and have used it
without any issues (both theoretically and in the real world) It uses the
same calculations as John Fullbright had illustrated with more considerations.
I ran the information you provided, if you can provide your average mailbox
size, User Concurrency, Disk Size, Disk RPMs, I will rerun it and give you
the projections.
Interesting enough it doesn't even provide recommendations for RAID1 on the
DB spindles.
Agreed Raid 1 does provide more performance, but I would expect to be given
my pink slip if I recommended it as a customer solution for a Database due to
the lack of redundancy and high risk we would assume.
Unless your users have a really high IOP Profile or really huge mailboxes I
wouldn't expect RAID 5 to be a bottleneck (unless you have your OS and
Transaction Logs sitting on the same Disks/spindles). Which isn't Best
Practice or Recommended by anyone I know (With all due respect).
You may also consider running Microsoft Best Practice Analyser to see if it
gives you any recommendations. Perhaps you have write cache enabled on the
drives?
I would also recommend you run performance monitor to see what the
bottleneck is before you spend money.
Here is a link you may want to check out for Troubleshooting Performance
with Exchange.
http://www.microsoft.com/technet/prodtechnol/exchange/2003/library/e2k3perf.mspx
--
Jonathan
No Warrenties Implied, Did you do a FULL backup today??????
"Asher_N" wrote:
> Another one of my pet peeves. Similar to the old, 'the arrow will never
> reach the target' problem. While your number are sound, any decent RAID
> controller has on-board cache. writes are cached and delayed until read
> are satisfied.
>
> So while the theorical problem points to fsaster writes with mirror, if
> you use the same drives and same RAID controler to do R1 or R5, you
> should get similar results. Also, 150 users is not much. I run 100 users
> on a single 5 drive partitioned as 2 logical drives (OS, Stores and
> logs). The performance is more than adequate.
>
> "John Fullbright" <Fullbrij@xxxxxxxxxxx> wrote in
> news:#eQkfp6FGHA.3936@xxxxxxxxxxxxxxxxxxxx:
>
> > I wouldn't do that, "three disks in RAID 5 for the Database .STM and
> > .EDB Files it would be 7 Disks.", that is.
> >
> > Let's assume a 3:1 read/write ratio for tha deatabases. We'll also
> > assume 10K RPM SCSI disks which are capable of ~85 20ms IOPS.
> >
> > Where P is the performance of a single spindle and N' is the number of
> > data spindles in the set:
> >
> > RAID 5 Read performance = P*N' = 85*2 = 170
> > RAID 5 Write performance =P*N'/4 = 85*2/4 = 42.5
> >
> > And we apply the read/write raitio which is required when read and
> > write performance are asymmetrical. With a 3:1 ratio we are 75% read
> > and 25% write:
> >
> > Performance = 170*.75 + 42.5*.25 =127.5+10.625 =138.125 IOPS
> >
> > If you were to buy bigger drives and go with just a mirror:
> >
> > RAID 1 Read performance = P*N = 170
> > RAID 1 Write performance = P*N/2 = 85
> >
> > Again we apply the read/write ratio:
> >
> > 170*.75 + 85*.25 = 127.5 + 21.3125 = 148.8125 IOPS
> >
> > My recommendation - Three mirrors for a total of 6 spindles. This is
> > about 8% better overall performance on the database array with 1 fewer
> > spindles. The write performance is a 100% improvement.
> >
> > Do the math.
> >
> > John
> >
> >
> >
> >
> >
> > "Jonathan Norris" <JonathanNorris@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
> > message news:D662866D-5331-4A4A-8B48-7EF998ABE340@xxxxxxxxxxxxxxxx
> >> Actually if i were to use two Disks for the OS (Raid 1) and two Disks
> >> for Transaction Logs (Raid 1) and three disks in RAID 5 for the
> >> Database .STM and
> >> .EDB Files it would be 7 Disks.
> >>
> >> Also keep in mind by having everything on the same spindles you will
> >> have an
> >> I/O bottleneck.
> >>
> >> OS/Page File is Read and Write intensive
> >> Transaction Logs are write intensive during normal operation and
> >> during recovery its read intensive.
> >> DB File .stm and .edb are both Read and Write Intensive.
> >>
> >>
> >> --
> >> Jonathan
> >> No Warrenties Implied, Did you do a FULL backup today??????
> >>
> >>
> >>
> >>
> >> "Ryan Burrus" wrote:
> >>
> >>> I am trying to find some information as to the recommended hardware
> >>> configuration for Exchange Server 2003. We only have about 150
> >>> users and all
> >>> access it using Outlook 2003. I have read a few things from
> >>> Microsoft that
> >>> says the Exchange data files and the page file should be on separate
> >>> drives.
> >>> Also that the Exchange data files and the Windows system files
> >>> should be on
> >>> separate drives. Also that the Exchange transaction logs should be
> >>> on a separate drive than the Exchange data files. This would equate
> >>> to 4 drives
> >>> which doesn't sound right to me. Does anyone know what the
> >>> recommended scenario would be for an organization our size? Any
> >>> advice would be much appreciated. Thanks!!
> >
> >
> >
>
>
.
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