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Marlon Brown · Guest

I am planning to partition SAN to prepare to migration to Exch2003.
My question is this:
I understand it is a good idea explore multiple storage groups (I will
create two). Based on the size of current database outlined below, do you
think the partitioning planning below looks alright ? Please advise.

Current Total size of Exchange db = 60GB
Total number of mailboxes=2,500, size/mailbox=70MB
Planning growth to maximum of 200GB db in 3 years.

C:(OS) two disks, Raid1 - Local server

D: PageFile -> Two disksx73GB, Raid1, SAN (73GB is more than enough)

E:\Exch Transac Storage group 1 ->Two disks x73GB, Raid1, SAN ( is 73GB
enough?)
F:\Exch Transac STorage Group 1->Two disks x73GB, Raid1, SAN (is 73GB
enough?)
G:\ Database files for both storage groups -> Four Disksx73GB, Raid5, SAN
(~200GB)

Marlon Brown · Guest

Found an update whitepaper on this. Here is the answer:
change system files - RAID-1 (direct-attached storage, not SAN)
· D:\ - Page file - RAID-1 (direct-attached

"Marlon Brown" <marlon_brownj@hotmail.com> wrote in message
news:uQq3aQOsEHA.224@TK2MSFTNGP15.phx.gbl...

Al Mulnick · Guest

Interesting.

Disk sizing is more an art than an exact science. That said, here's some
thoughts based on some things I've seen.

Transaction files - you need one set per storage group.

You want to use storage groups as a way to scale larger servers. So you can
have a single storage group and just build several databases internal to
that storage group. I usually work it backwards from the disaster recovery
times I want. For example, if I want to recover data in 1 hour, I need to
know how fast I can put data back. If it's going to take me 1 hour to put
back 25 GB of data per stream of restore, then I may want more storage
groups. That's because I can restore to multiple storage groups (SG's) in
parallel. I can only put back one db at a time in serial within a SG.

So, I also have to take into account my log file growth/performance. I
don't want log file stalls, but since log files are typically characterized
by sequential write I/O, I often try to put them on the their own physical
spindles to avoid disk contention issues. But because they're mostly
sequential, I'm not as worried about their performance or disk sizes if they
are dedicated spindles. I'm just concerned that they're fast, reliable, and
fault tolerant (they're the most important part for recovery).

The DB's, STM and EDB files, typically have a random r/w characteristic. So
if you use shared spindles, you can often get away with grouping them more.
Just be careful to watch for r/w response times out of spec.(see
http://www.microsoft.com/exchange/library for the troubleshooting
performance doc for some more detail there).

Back to the drive layout.

Using two SG's has the advantage for you that you can put 1250 users per SG,
or 1250 / 4 ~ 312 users per database in each SG. Depending on limits you
set, that may be within spec for you. It may be larger than you want to go
necessitating a third storage group.

Usually, to get disk requirements, we try to break the calculation down to
IOPS. Every hardare uses pretty much the same criteria for that. They
assume you can get about 90-120 IOPS worth of performance per phys disk if a
10K RPM drive. If you use a 15K, you may get higher (think 120-160 IOPS
depending on load). That means you need to figure out what your user
profiles are. Are they medium users that need about .5 IOP each? Or are
they heavy users that need >1 IOP each for acceptable performance? You'll
need to figure that out. You may also want to look at single instance
storage to see how the move will affect you. You'll lose some of that SIS
when you split it among different stores.

Will your layout work? That depends on the above. Also, why bother putting
the swap on a second drive? Hoping for the extra performance boost?

Be sure to align the track sectors for your system. It's a huge difference.

Al

"Marlon Brown" <marlon_brownj@hotmail.com> wrote in message
news:ecMnZDYsEHA.624@TK2MSFTNGP09.phx.gbl...

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