[SUMMARY] Solstice RAID 5 should I trust my system on it.

From: David Gempton (ttcdg@cyberspace.co.nz)
Date: Mon Mar 11 1996 - 02:03:06 CST


Original Question:
=======================================
> Hi fellow system managers.
>
> Im looking at upgrading the disk capacity on a SServer 20. The file =
> system in question is currently running a mirror set made of 2x2.1GB =
> drives. Yielding 2.1GB of usable space.
>
> What I am thinking of doing is moving to Solstice RAID 5 software and =
> adding 2 more 2.1 GB drives. This should give me 6GB of usable space.
>
> My question is does anyone have any experience good or bad with the =
> Solstice RAID software running on Solaris 2.3. I absolutely do not want =
> to compromise the reliability of this system.
----------------------------------------------------------------------------------
Summary of responses
=========================================
In general it was recommended not to run this product on Solaris 2.3 due to the buggy nature of early versions of Solstice and Solaris 2.3.

Once upgraded to Solaris 2.5 the stability should be fine. However there will be quite large i/o degradation to the RAID 5 disk set.

Short of going to a hardware based RAID solution, disk mirroring is by far the best option for Solaris 2.3.

Hardware based RAID solutions are vastly superior to software ones in functionality, performance, and reliability.
-----------------------------------------------------------------------------------
Responses
==========================================
Doug Jones
> My question is does anyone have any experience good or bad with the Solstice RAID software running on Solaris 2.3. I absolutely do not want to compromise the reliability of this system.
>

Then upgrade to 2.5 (much more stable than 2.3+patches, +patches, +patches....)

And I would also say that I am very happy with the RAID 5 soultion with ODS. I have been
running a RAID 5 using ODS 4.X for 7 months now with no problems.$.02
------------------------------------------------------------------------------------
John Hogue

David,

A few quick thoughts.

1. Upgrade to 2.5 if possible. 2.3 is a little buggy.

2. Use Solstice DiskSuite 4.0 if possible (again, previous versions,
   are buggy).

3. Expect write performance degradation.

4. Use as much prestoserve (NVRAM) as you can afford on the
   system if you are going to be using RAID.

5. If write performance is an issue, spend the money on new disks
   and mirror them instead of using RAID.

6. Good luck.
---------------------------------------------------------------------------------------------
Gary Lee

There are a number of RAID vendors out there. I am not
sure who sells what in NZ. Hardware solutions are better
than software ones. I really wonder why you want
RAID on such a small (in terms of disk capacity) system.
The current industry standard for 3.5" disks is ~4GB of
formatted capacity and for 5.25" is 9 GB. This summer
you can expect 8 GB formatted 3.5" disks. Remember that
the failure rate of your system will increase simply because
you are using a lot of small disks.
----------------------------------------------------------------------------------------------
Ed Romascan
> I absolutely do not want to compromise the reliability of this system.

David -

If you mean this you should use an HP AutoRAID system. The fully redundant
version has no single point of failure and can continue working through the
failure of two disks on a six disk system.

I have attached some info. We, of course, sell the units.

A 12Gb unit - about 8GB usable runs $15,100 and a fully redundant unit runs
$20,031.
-------------------------------------------------------------------------------------------------
Ram

Dave,
I haven't seend any problems so far with RAID 5. However, I use RAID 5
with HostSpares. The only problem is the IO performance it Not Good at
all. I see a 20 - 30 % degradation when compared to a non-ODS disk.
These numbers are when everything is normal and healthy. So I figure,
when ODS has to do a rebuilt of partity info, it will much worse.
---------------------------------------------------------------------------------------------------

I would shy away from Solstice Disksuite on soalris 2.3. Upgrade to solaris 2.4
before using raid 5 (strictly my opinion). Four disk is considered a minimun, better of with 5+ ... obviously depending on your load. Also remember the write performance with raid 5 is usually slower the other methods. Soooo if you environment is write intensive you may want to combine raid 5 with the addition of nvram.
---------------------------------------------------------------------------------------------------
Jos Speck
Hello,

Well i did some tests on RAID-5 when whe get
a new departemental Server.

** When there are a lot of writes through the disk
   you get a worse perfomance i did some measurments
   on it, writing a file to an local-fs takes 1 sec.
   and writing to a RAID-5 -fs takes 5 sec.
   So the performance of the system then is bad...

** But the advantage is that you not need a lot of
   disks to make a more available system.

At our site whe are dealing with mirroring,striping and
UFS-file logging.



This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:10:55 CDT