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Critical decision – How many arrays?

New big server x440 is coming with 14 2Gbps FC 73.4GB 15K Hot Swap HDD on IBM Total Storage Fast Exp700 exp.Unit.
This server is for SQL Server and file system only.
The idea is to have 6 HDD per Expansion unit on Raid 1 level with 2 hot spare.
I need advise on making arrays.
My idea was to have only one array and make partitions on it at the OS level.
Is this safe or are there other configurations more correct that you can suggest like maybe one array for SQL Server and another array for file system,log and backups?.
Just a little confused on this topic.
Thank you in advance.
Best regards.
If you do that, you’ll eventually have issues. There is no way to isolate the load on one logical from the load on another. heavy database read activity can affect your logs, or heavy logging can slow down your database. A backup could kill everything. You’ll want seperate arrays to ensure isolation. A RAID 1 for the OS, a RAID 1 for the logs, and a RAID 10 for the databases would be ideal. For backups, well..
If you plan to backup to disk and roll the flat files to tape, a RAID 0 is fine. You could have a couple days on disk, and further back on tape. If you plan to use disk only, then you should seriously reconsider your backup strategy. If you go with four arrays, Set the allocation unit size for the OS to 4K, the logs to 8K, the databases to 8K, and the backup drive to 64K. You can check my other posts for further storage tuning tips. John
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