🚀 go-pugleaf

"Unknown" <thisandthat@hereandthere.oz> wrote in message
news:gYG%b.183$S65.7163@nnrp1.ozemail.com.au...
>
> " Miro" <miro01@hotmail.com> wrote in message
> news:403f388e$0$20139$afc38c87@news.optusnet.com.au...
> >
> > "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.
> >
> >
>
> Nothing to do with what I said above, a few letters back though....
>
> A HD can die on a raid and not affect any other HD.

No it can also screw the data bus and make the I/O rate climb till it cant
do anything useful. Your assumption is not without its holes.