🚀 go-pugleaf

"Unknown" <thisandthat@hereandthere.oz> wrote in message
news:seG%b.165$S65.6424@nnrp1.ozemail.com.au...
>
> " 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.

Look at it this way. Some hard drives just curl up and die, others flop
around like B-grade actors and just cant seem to get the whole death thing
into perspective. Admitedly sudden death is far more common, but not the
only style of data decapitation.