SUMMARY:Concatinated RAID 5, SSA and Solstice Disksuite

From: David Robson (
Date: Thu May 01 1997 - 09:34:37 CDT

Sorry! Dreadfully late with this! :-(

I didn't get a lot of joy with this, but I'll tell you the story so far...

My problem was (is) using Online disksuite to create RAID 5 metadevices and
concatinate them together. After an informal discussion with a chap from Sun and
after reading a white paper from Sun, I believed it might be possible. The URL
for this paper is:

I have tried to do it, but metatool won't let me. Sun as yet have not
confirmed whether their other product (Veratese?) can do it. Although one of
the sun-managers that replied indicated that it couldn't. :-(

Since mirroring will never be an option (as another storage array is around
$70K), I have to make do with RAID 5. I will need to look at the disk
consumption rates and work out how to divide our system across much smaller
metadevices (for performance).

Thanks to:

Glenn Satchell
Stuart McRobert <>
Matthias Kurz <>

My original post:

We have a fully populated SSA. 12 disks are 1.05 GB, the rest are 2GB.
After getting burned with a disk failure we reconfigured the SSA for RAID 5
rather than a huge concatinated stripe (RAID 2?) using Solstice Disksuite v4.1
At the time we wanted the redundancy, but didn't want several small partitions
which would make managment a problem. We ended up with two large RAID 5 devices.

Later when performance problems became apparent, Sun adviced that more than 6
disks in a RAID 5 stripe was _bad_ and they gave me the URL for a Sun white
paper on RAID. This paper suggested that we can create RAID 5 stripes, each with
six disks, and then _concatenate_ them together to make lager devices!
Somehow we missed this in the documentation for Solstice Disksuite, as had
we known, this is exactly what we would have done.

My question is: Has anyone done this or heard of it being done with Solstice
Disksuite? Any known problems or gotchas?

If this works it will save us a major headache and improve performance... 8-)
A summary will follow of coarse! :-)


Robbo (David Robson)
Davtin Systech Pty.Ltd.

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