I am allowed 6 drives for my SQL Server boxes and usually configure them as follows:
2 drives as a mirrored pair - boot partition goes here and another drive
letter for the transaction log
3 drives in a RAID5 array - data goes here 1 singleton drive - nonclustered
indexes go here (and I create a script for use in case this one fails that
drops all the nonclustered indexes and re-creates them on another drive, so
the database can stay up until the bad solo drive can be replaced)

So, the first one I did like this, the singleton and mirrored drives are
only 18 GB each.   (The three RAID5 ones are 72, which is fine.)  This is
plenty for
the singleton for that database, but is really too small for the mirrored pair
-- currently the boot partition is only 4 GB and the NT admin says it HAS to
have a swap file of at least 1.2 GB (I wanted to move the swap file to the
singleton drive) and my transaction log is about 11 GB by the end of the
day.  I would like more headroom for the transaction log because I'm
getting at least 100 net new users by the end of the year so there will be
considerably more activity, and he says we should have 8 GB for the boot
partition because there isn't enough room for applying patches.  Also the
box is constantly showing memory usage at 85% or more -- we are going to
add RAM (somehow it only got 1 GB) but squishing the swap file isn't
helping. 

I asked whether we could replace the two 18's in the mirrored pair with
36's and he freaked.  Finally after thinking about it he said he wants to
know whether if we do this we will screw up anything with the other 4
disks.

And I want to know what else we should be worrying about.

TIA   :)

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