Your Opinion - Disk

(9.2 on Solaris)
Our disk configuration is as follows. We have 2 logical disks each consisting of 4 physical disks configured with RAID5.

/d01
user_data.dbf
tools.dbf
hk_data.dbf
temp_01.dbf
redo01a.log
system_01.dbf
stage_data.dbf
wms_index.dbf
undotbs_01.dbf
redo02b.log
control_01.ctl

/d02
redo01b.log
stage_index.dbf
wms_data.dbf
redo02a.log
control_02.ctl

And a third single disk for /archive. What my sys admin and I want to do is reconfigure the disk pool (Sun T3) to 4 RAID0+1 disks and purchase another T3. In this way we go from a 3 disk system to a 9 disk system (two 4 RAID 0+1 disks and /archive disk). I am also aware that it is critcal to get the redo logs off of RAID5.

Can you please share your thoughts on my current situation (disk crowding) and my new direction so that I may learn better.
Thank you!

More disks == better perfomance.

The 0+1 filesystems will definitely do better than the RAID 5 filesystems, especially if they are spread out on two controllers. As you know, redo on RAID 5 is bad news. Also, I would put your ORACLE Software and TEMP on the single disk and not archive. IMHO, archive is much too important to be NOT protected.

T3's use Hardware RAID, right? Even so, SW RAID and 0+1 will be better than SW RAID 5 anyday.

As for raid5, I have a question:
If i have 8 disks, one configuration is for raid5, another option is for raid10.
For the performance of read operation(read mostly), which configuration will give better performance? According to your experience?

Read operations on RAID5 and RAID10 are more or less equal performance-wise.