[rescue] Ultra 2 upgrade question...

[Janet L. Campbell]

On Mon, 4 Apr 2005, Sandwich Maker wrote:

> " From: Phil Stracchino <phil.stracchino at speakeasy.net>
> " 
> " Patrick Giagnocavo wrote:
> " > I have had poor results with software RAID and Solaris.  Not sure
> " > why... it does work, just slowly.
> " 
> " You surprise me.  I have eight disks RAIDed with Solstice Disksuite (or
> " whatever Sun's currently calling it) on a single-250MHz U30 running
> " Solaris 9, and it can easily saturate a 100Mbit connection.
> " 
> " That is, to be fair, just a stripe, not RAID5.
> 
> apples and oranges.  striping - especially across controllers - is a
> great way to improve disk i/o.  raid5 requires the metadriver to
> calculate/analyze ecc sums on the fly every time there's an i/o.
> that's the penalty you pay for the ability to pull one of your raid5
> disks out without crashing your system.

...and last I checked (admittedly, Solaris 7), the Solaris metadevice 
driver wasn't multithreaded, so you won't get any use of a second CPU.

Kind of sad, really.  We had a SS20/812 here that was bottlenecking on a 
simple raid0 stripe, and a non-Disksuite solution (writing to separate 
disks manually) ended up being far faster.  The box had plenty of I/O 
capacity.

-Janet