FWIW
We had some issues at one of my previous employers where Mirror/iX would
choke if you ran sysinfo. (I think it was sysinfo anyway)  It would cause
some of the drives being queried to drop out of sync.  This too may be
related to the excessive I/O issue though since as I recall the system was
heavily used.  I have even heard rumors were it crashed the system, but I
wasn't there for that.
____
Tony Newton  |  [log in to unmask]
HP Systems Admin  |  (503) 574-5831
Providence Health Plan  |  www.providence.org



> -----Original Message-----
> From: Chris Bartram [SMTP:[log in to unmask]]
> Sent: Thursday, January 20, 2000 10:10 AM
> To:   [log in to unmask]
> Subject:      Re: Mirror/iX
>
>  In <[log in to unmask]> [log in to unmask] writes:
>
> > Andreas Schmidt wrote:
> > > So, from our perspective, we can say
> > > * Mirror/iX is a cheap solution compared with Disc Arrays to ensure a
> high
> > > availability on business critical servers,
> > > * the SCSI drives & interfaces are very reliable,
> > > * the repair process (if needed) is proven and straight forward.
> >
> > This exactly matches my former customer experience with Mirror/iX at
> cccd.edu.
>
> (speaking for a site I manage)
> We're somewhere in between. We've lost about 8-10 mirrored discs in the
> past
> year (out of a set of 18 pairs of 4.3Gb drives), but have yet to require a
> reload (i.e. no lost data on the mirrored discs). Mirror/iX does seem to
> "agressively" flag discs as bad, and we've had some problems with discs
> dropping offline (due to what HP suspects is excessive i/o rates -
> probably
> due in part to some mirrors not being on separate channels... a problem we
> recently discovered on a system that HP (mis)installed).
>
> We've also lost 3 of the same model discs on non-mirrored volumes in that
> same
> period; 3 reloads of those volume sets.
>
> It does seem to reduce i/o loads; our 997-400 runs VERY high i/o rates,
> and
> I suspect we'd be seeing serious performance problems without it.
>
> Overall, it seems to help our performance a bunch; we haven't lost ANY
> data
> (despite all the dead discs), but had a LOT of false alarms. All told I'd
> have to recommend it (much better than no mirroring, and splitting reads
> across mirrored pairs helps i/o throughput alot).
>
> That said we also bought an XP256 disc array (though pricetags on those
> beasts are not for the faint of heart - 1Tb was about $1M) and are
> experiment-
> ing with that as well. We were *extremely* disappointed to find out that
> the
> 100% redundancy on those units doesn't apply to connections to HP3000s,
> which
> don't allow redundant/failover paths to the array. So much for the 5 9's.
>
>    -Chris Bartram