SUMMARY: Best way to configure RAID-5 under Solaris 2.6?

From: Maccy <>
Date: Sat Oct 06 2001 - 06:14:28 EDT
Hi all,

My sincere thanks go out to (both on the sunmanagers and veritas-vx lists)

Roger Leonard
Mark Hargrave
Stan Pietkiewicz
Chris Biggins
Darren Evans

The reason I was only getting 474 GB out of my 800 GB capacity was due to
Veritas's column default setting. Increasing this to 7 meant I could get
630GB, more like what I expected. As many of you pointed out though, RAID 5
writes are very poor, might have to consider another config! I will also be
trying the different software suggested - many thanks again.

The most appropriate answer was from Stan :-

"One thing I noticed when I had a few empty disks to play with in Veritas
Volume Manager: The usable space in a RAID-5 volume varies with the number
of columns. I don't remember the exact numbers, but 4 columns had a 33%
overhead (100 gb of space used 133 gb of disk), 3 columns (VVM default IIRC)
had a 25% overhead, 5 columns 22%, and gradually decreasing with an
increasing number of columns. The exact numbers are from memory (and reality
may differ from my memory), but I recall the worst being 4 columns, with 3 a
little better, and 5 better yet.

Another black hole for disk space is a spare disk... Yes, you really do want
to set up a spare disk.... Did VVM set up more than 1 spare disk by default?

Does VVM see all 22 disks, and are they all in the same disk group?"

> -----Original Message-----
> Sent: Tuesday, October 02, 2001 3:35 PM
> Hey all,
> I have 22 x 36GB (Total 792 GB) disks in a Sun StorEDGE A5200 Array, fibre
> connections. I'd like to know how what the easiest and quickest way is to
> set these disks up as a RAID5 set on an E4500 running Solaris 2.6.
> Playing around with Veritas Volume Manager, and accepting the defaults for
> RAID-5 volume, the max I can get out of the array is ~474 GB?! Maybe I am
> doing something wrong, is there something special I must do?
> Has anybody done this effectively using Disksuite or Storedge Component
> Manager? I can't see any way to arrange my disks into a RAID set via the
> latter easily, only monitor the disks separately. 'Format' shows up all
> disks separately.
> If anybody can talk me through the various steps I'd be very grateful, or
> just to share comments and experiences. I will of course summarise.
> BTW many thanks to those who responded to my last query after I summarised
> about connecting to my E4500 via a serial connection.
> Best wishes,
> Mark Mahabir
> University of Leicester, UK

sunmanagers mailing list
Received on Sat Oct 6 05:13:36 2001

This archive was generated by hypermail 2.1.8 : Thu Mar 03 2016 - 06:42:26 EST