Array configuration for Exchange 5.5

[Ayman Altounji]

Exchange 5.5 help indicates that the recommended disk configuration is as follows:

a. A physical disk containing the operating system and the page file.
b. A physical disk for the transaction log files so that they can be written to sequentially. To increase fault tolerance, you can mirror the disk containing the transaction log files.
c. A stripe set consisting of multiple physical disks for all other Microsoft Exchange Server components so that the Microsoft Exchange Server databases can be accessed most efficiently.

I have a Compaq Proliant 1850R server with four 9 GB drives and 1 GB RAM. If I follow the above guidelines I end up with one 9GB drive for the OS, one 9GB drive for logs, and two 9GB drives for 18GB assigned for the databases, etc. All drives use RAID 0. This setup seems insecure as it only uses RAID 0 and inefficient as I have more space than needed for the OS and logs. Does anyone have any opinions or advice for me on this issue? How should I configure the array?
Thanks in advance. - Michael

[Ayman Altounji]

Here's a thought, for the OS and page file, use disk 0, then setup a RAID 5 using disks 1,2 and 3. Make 2 partitions, 3 GB for the logs, and the rest for the databases. I had a similair issue with a system and found this to be a happy comprimise as the actual data is far more important than the OS, sine that can be reinstalled quickly. Just be sure to make 2 back-ups every time you update the software (to follow Microsofts recomended 3 copies idea) this will ensure that while the system may go down, it will be back up [relatively] quickly.

[Ayman Altounji]

Fault tolerance is the first thing you should consider. Its insane to put the logs on a single disk without fault tolerance. So two ways to do it........
1: Raid 5 the lot. then partiton as you see fit. Its not ideal but its better than single disks for OS and logs.
2: The ideal......get a 4314 external storage box. mirror the OS with 2 of the nines. Mirror the Logs with the other 2 or get some 18gb disks. Buy some more disks and either RAID5 or RAID 0+1 them for the message store.
Believe me you don't want to be doing an exchange restore because the single OS disk died..........
Oh and don't even consider using software mirroring.