Re: RAID 5 Partitions

Paul Sheahan ( (no email) )
Mon, 27 Jul 1998 13:45:22 -0400

>We have a situation where we have 3 9GB drives in a
>Tangent Enterpise Server w/hot swap drives. System is
>fully redundant.
>
>Drive Configuration:
>
>Partitions:
>
>DISK 0 C:\ FAT 1028 D:\NTFS3342 FREE SPACE=4346
>DISK 1 E:\ NTFS 4738 FREE SPACE=3977
>DISK 2 F:\ FAT 4001 FREE SPACE=4714
>
>Tangent says their hardware raid system will cause the C:\NT 4.0
>partition to be supported and bootable with RAID 5.
>
>QUESTIONS:
>
>1. DO YOU NEED TO PARTITION THE RAID 5 STRIPE SET AS NTFS OR AS FAT?

I haven't seen or heard of an NT bootable RAID5 system. But if it can be
done as Tangent says, you can use NTFS or FAT. Use FAT only if you are dual
booting another OS that can't support NTFS. Otherwise, always use NTFS as it
provides better performance than FAT on any drives over 400 meg, among all
of the other security features.

>2. WILL FAT OR NTFS PARTITIONED DRIVES WRITE TO A RAID 5 STRIPE SET
>WHICH IS EITHER FORMATED AS FAT OR NTFS [EXCHANGABLE]? AND DOES
>THAT EFFECT RECOVERY SHOULD A DRIVE GO DOWN?

FAT or NTFS doesn't matter, all access and recovery options are the same on
RAID5.

>3. ARE RAID 5 PARITY STRIPE SETS ASSIGNED A DRIVE LETTER OR DO YOU
>LEAVE THEM WITHOUT ANY?

The whole stripe set is assigned the next available drive letter by default.
But you can reassign the drive letter afterward...

>4. DOES IT MAKE MORE SENSE TO CREATE A RAID 1 MIRROR SET FOR THE C:\
>DRIVE. THE SAME FOR THE F:\FAT DRIVE PARTITION & WHAT'S LEFT OVER AS
>RAID 5 PARTITIONS.

RAID 1 is optional and obviously provides better fault tolerance if you use
it. For best performance, place the paging file on a drive NOT included in
the RAID5 array and NOT on the same physical drive as the \WINNT directory.
NT will take a performance hit in these cases.