Promise Technology 66 Pro - Manual (Page 115)

SuperTrak66™ User's Manual Chapter 6
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One solution is to create two (2) mirroring (RAID Level 1) arrays using four (4)
drives (2 drives per array). Array 1 can be used for the bootable system files. Array
2 can be used for the user or data files. With SuperTrak66, Array 1 would consist
of drives 1 and 3, while Array 2 would use drives 2 and 4. Such a mirroring array
architecture effectively boosts the performance of each array as well as providing
data redundant data storage. In this configuration, heavy swap file access on Array
1 under significant load will not affect the transfer performance of the user/data
array (Array 2).
Mid-Sized Windows NT Application Server
As previously described, it is best to separate the system/boot drive from the
user/data drive because of the intensive file swapping I/Os which the disk system
is subjected to from normal operation of Windows NT under heavy loads. For an NT
application server, there are three possible recommended configurations for
performance and reliability:
1) Striping/Mirroring (RAID 0+1) - 4 drives total. Two (2) drives are
striped together and mirrored to two other striped drives. This provides
good performance for read/write operations as well as single drive fault
tolerance.
2) Block and Parity Striping with "Hot" Spare (RAID 5) - 4 drives total:
3 drives striped with rotating striped parity, and 1 drive una ssigned as
a "hot spare”. This provides performance similar to configuration #1
above, but also offers better drive fault tolerance with immediate drive
rebuilds.
3) Block and Parity Striping (RAID 5) - 4 drives total: all drives striped
with rotating striped parity. This provides excellent read performance
and single drive fault tolerance.
Configuration #1 exhibits good reliability from fault tolerance and good data transfer
performance. Configuration #2 yields excellent reliability and good data transfers
(though slower on writes than #1). Configuration #3 offers excellent performance
and good reliability. The choice of which configuration to use should be made
based on your particular needs to balance performance with data protection.