On Fri, Nov 19, 1999 at 09:57:44AM -0800, Matthew Brown wrote:
> John White wrote:
> > IMHO, no software mirroring scheme is going to do the trick. AND
> > they're overwhelmingly expensive.
>
> As to the latter point, isn't DiskSuite included in your Solaris license
> these days?
No. One has to buy a special edition of the OS to get DS.
> On the former point: why is such a huge proportion of the world doing their
> mirroring with software RAID (generally Veritas) including some HUGE solaris
> installations (Sun seems quite keen on Veritas).
Probably because those installations are supporting a qmail queue
on their giant SW RAIDs.
> > Software RAID is, again IMHO, not suitable for making your queue
> > redundant or quick.
>
> I've met many people who are of the opinion that software RAID is no slower
> than most hardware RAID. Or is the 'most' the important word here?
The phrase "writeback cache" is what's important.
Disk i/o is a bottleneck. SW RAID 1 exacerbates that bottleneck.
If redundancy is all you want, I'd reccomend a HW RAID 1 with a cache to
smooth out the spikes in usage. If you needed continuous high performance,
I'd go with a 1+0 configuration with more cache AND a journaled fs.
John
