Best IO performance

[IT_2007]

Any thoughts for the following:

Striped file system is full and need to extend it. Logical volume stripe size is 64k with stripe set of 8 disks with RAID 5 on HP XP1024. This file system can be extended by adding another stripe set of 8 disks. But what I am really interested to know is HIGH IO performance by using which methods??

1. Create a new stripe set of 16 disks and copy from old file system ?

or

2. Add another stripe set of 8 disks and extend existing logical volume?

Appreciate any supported documents/benchmarks etc..

[Steven E. Protter]

Shalom,

1 is rated by most disk builders as more effective. More spindles increases the chance of reads happening faster.

Writes may be a bit slower so be careful.

Most disk array software lets you rebuild and stripe while running.

SEP

[Wessam Aly]

Since you are already using RAID 5, I see no reason for striping. The basic architecture of RAID 5 on enterprise storage arrays like the XP is that the RAID 5 groups already use a large number of disks and read/write operations are distributed among several spindles.
re-striping your reads/writes may sometimes worsen the performance. Ofcourse this depends on the type of data and type of access.. is it mostly read ? mostly write ?
depending on this, you may improve performance (but only marginally) if you strip.
in your situation, may I recommend that you create another 8-disk set and split your data into two categories, one set of high reads and another for high writes.
This should give you maximum performance.