🚀 go-pugleaf

" Miro" <miro01@hotmail.com> wrote in message
news:403ea6bb$0$19707$afc38c87@news.optusnet.com.au...
>
> "Unknown" <thisandthat@hereandthere.oz> wrote in message
> news:FDv%b.61$S65.1164@nnrp1.ozemail.com.au...
> >
> > " Miro" <miro01@hotmail.com> wrote in message
> > news:403e7c97$0$28870$afc38c87@news.optusnet.com.au...
> > >
> > > "Leythos" <void@nowhere.com> wrote in message
> > > news:MPG.1aa7bde53e86577498a268@news-server.columbus.rr.com...
> > > > In article <403DDBE5.67A77D68@ozemail.com.au>,
> > > > audiobANTISPAM@ozemail.com.au says...
> > > > > Scott Coutts wrote:
> > > > >
> > > > > > Yeah, sure. I dont doubt that it can be faster. But it's also
true
> > > that
> > > > > > they can be slower... when all the motherboards started coming
out
> a
> > > > > > while back with built in RAID controllers, people were going out
> and
> > > > > > setting up their RAID arrays and thinking how much faster it
would
> > > be...
> > > > > > but those setups often just dont cut it (: They're OK for backup
> > > > > > purposes I guess.
> > > > >
> > > > > RAID 1 generally offers higher performance than a single drive
with
> > > > > twice the risk of failure.
> > > >
> > > > RAID 1 is a mirror - two drives hold EXACTLY the same information.
> While
> > > > you have twice the chance for a drive to fail, you only have half
the
> > > > chance for data loss due to failure of any drive. In the real world
> that
> > > > means that loosing a single drive does not impact the user.
> > > >
> > > > RAID 0 is a stripe across two disks - this provides twice the chance
> for
> > > > mechanical failure and twice the chance to loose everything in the
> event
> > > > of a mechanical failure. Loosing either drive results in the
complete
> > > > loss of everything.
> > > >
> > > > RAID 5 is a stripe across 3+ disks with a parity stripe used to
> rebuild
> > > > the other drives in the event of a failure. In this situation you
can
> > > > tipple your chance for a mechanical failure, but you benefit from
> being
> > > > able to replace the defective drive and rebuild the entire array
> without
> > > > the loss of data. During the time a drive is lost, you will notice a
> > > > significant performance hit.
> > > >
> > > > Mechanical failure does not always mean data loss - only RAID 0 in
the
> > > > example above suffers from data loss.
> > >
> > > Really, what happens if you blow two drives in a raid 5 setup ? Dont
say
> > it
> > > never happens, it did.
> > >
> > >
> >
> > I'm still confused about those RAID answers. Why the hell cant you use a
> > simple raid setup to have yet another HD attached to a computer and that
> HD
> > simply for backups? Eg, similar to having a Master on primary and a
Master
> > on Secondary off the motherboard. Thus, if C screws up and as you have
> been
> > good people and done backups all the time, just attach raid drive to
> primary
> > or secondary port, boot off Drive Image 7 CD (just for example, not that
I
> > am pushing the program) and restore. Buggered if I know why a suddenly
> > scrambled C drive that wasn't scrambled because of a hardware fault
would
> > affect a raid mounted HD as suggested above.
>
> I once spoke to a very sad IT manager. He had a mirror setup for his boot
> drive. When the main drive started to wig out and write garbage the RAID
> controller obliged by writing garbage to the mirror. Thus killing both
boot
> disks.
>

It's pretty damned obvious why a real time 100% of the time backup would
stuff up if you mirror C elsewhere and expect elsewhere to work continuously
every single time when C fails.

> The magical assumption that a hard drive just dies isnt valid. It can do

Rot. I have had that happen even to my own computer. Back when 20gig was a
medium sized drive, I had 2 and C died in 6 weeks. By then 40gigs were about
and I bought a 40gig for C drive and restored from backup. No problems. What
I do is have the other drive as a backup drive only where mirror images are
stored but as my data doesnt have to be correct to the nanosecond, I only do
mirrors 2 times a week (auto). I have compressed images on that drive. HDs
DO just die and saying they dont is just plain wrong.

> some very strange things in the read/write cycle and cause no end of
bother
> on the data bus. Having said that, some software, such as databases also
> likes to write pre-and post- cache files which require a stable read-write
> cycle to marry up data changes. You can join the dots on the rest.

Sure. That goes back a long way. I remember old 5.25 drives where you write
something to it and wait. The drive light had to go out then let 30 seconds
pass and it would come on again for a few seconds and go out again. THEN you
could remove the disk. Doing it before that ended in dead data. However,
what you said doesnt have any relevance to the last sentence of what I
posted above.