RAID 1

[Guest]

I know RAID-1 gives redundancy and will allow one disk to back up the other
in event of failure of one disk. What I want to know is if I implement a two
disk RAID-1 configuration in WIN XP and the normal C:\ boot disk fails, will
the computer boot up on the 2nd disk after it has been switched off?

 

[DL]

Raid1 - mirror - doesn't 'backup', the drives are exact clones.
If one drive of the mirror fails, you have to physically disconnect the
failed drive, sys will then boot on the good drive. There can be problems in
ascertaining which drive has failed, it depends on the raid utility used, or
the use of a separate disk checking utility.
I'm assuming a hw raid.

 

[Richard Urban]

And that only works if you have a hardware failure. I will venture a guess
and state that the majority of "unbootable" computers suffer from disk
corruption, bad drivers, incorrect versions of necessary files, machine
infestation etc. Remember, bad drivers, machine infestation, deleted files,
incorrect installed files etc. affect BOTH drives. The machine still will
not boot.

I believe that a second drive (external is best) can be better utilized as a
repository for saving of drive images of your system drive. These images are
created manually, when you "know" the machine is in a competent state of
operation. Doing this, you can "always" recover from a defective system
drive, no matter what the cause.



--
Regards,

Richard Urban

aka Crusty (-: Old B@stard

If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!

 

[Ken Blake]

In

I know RAID-1 gives redundancy and will allow one disk to back
up the
other in event of failure of one disk. What I want to know is
if I
implement a two disk RAID-1 configuration in WIN XP and the
normal
C:\ boot disk fails, will the computer boot up on the 2nd disk
after
it has been switched off?

Raid 1 is designed to be used in a business situation where
downtime can't be tolerated, so that the second drive takes over
from the first seamlessly without a delay. It is not meant as a
backup solution and shouldn't be used for that purpose. Companies
that use RAID 1 *also* put backup strategies in place.

The problem with using RAID 1 for backup is that your backup is
stored within the computer. It therefore leaves you susceptible
to simultaneous loss of the original and backup to many of the
most common dangers: severe power glitches, nearby lightning
strikes, virus attacks, even theft of the computer.

In my view, secure backup needs to be on removable media, and not
kept in the computer. For really secure backup (needed, for
example, if the life of your business depends on your data) you
should have multiple generations of backup, and at least one of
those generations should be stored off-site.



My computer isn't used for business, but my personal backup
scheme uses two identical removable hard drives, which fit into a
sleeve installed in the computer. I alternate between the two,
and use Drive Image to make a complete copy of the primary drive.

 

[Guest]

Richard, yes I understand all of that but I don't have a probelm with
drivers, virus's etc. I keep my machine very up to date. Thanks anyway.

 

[Guest]

Ken, I do backups too, mostly to DVD. My problem is the real time failure in
an office where the operator is not pc savvy and a problem needs to be fixed
immdiately. So at failure of a disk, I want the other disk to take over until
I have time to fix it by replacing the faulty disk, hence my original
question. The problem with backups, is that they are done daily, and this is
not good enough for an immediate fix to a failure. So I suppose basically it
is not backup of the data which I am trying to protect in this instance, it
is actually backup of the hardware. Bye. David.

 

[Ken Blake]

In

Ken, I do backups too, mostly to DVD. My problem is the real
time
failure in an office where the operator is not pc savvy and a
problem
needs to be fixed immdiately. So at failure of a disk, I want
the
other disk to take over until I have time to fix it by
replacing the
faulty disk, hence my original question. The problem with
backups, is
that they are done daily, and this is not good enough for an
immediate fix to a failure. So I suppose basically it is not
backup
of the data which I am trying to protect in this instance, it
is
actually backup of the hardware. Bye. David.

Then it sounds like you *are* in the right kind of situation for
RAID 1. I misunderstood when you said "will allow one disk to
back up the other." Sorry for my lecture then; it doesn't really
apply to you.

 

[Guest]

Thanks. You have answered my question exactly, but another comes to mind. Do
the two disks have to be exactly the same size or can disk "2" be larger than
disk "1", (i.e. the C:\ boot disk)? If "Yes", then how does the BIOS and XP
suddenly cope with a new different (larger) boot disk, or isn't this a
problem with a mirrowed drive situation? David.

 

[Guest]

Hi Ken,
I didn't take it as a lecture! All advice is accepted gratefully. Thanks for
your help. Bye. David.

 

[Guest]

Hi DL,
I just realized by answering anohter post on this thread that I am not
trying to backup my data, (I do that anyway). I require continuity of
hardware service, so basically, I want the machine to continue to operate
when a drive fails. It appears from the advice received from yourself and
others that this RAID-1 is the way to go. I am just waiting for your response
to my second post to you. Thanks. Bye. David.

 

[Star Fleet Admiral Q]

David,
Basically yes, depending on the type of RAID controller card you are
using! Some allow you to switch between the drives, and others require you
to break the mirror, then choose which to boot from, then of course, once
the issue is fixed, how to synchronize the drives and reestablish the
mirror. You just need to be familiar with the correct keys to press to
enter the controller cards BIOS/CMOS when needed, unless the RAID controller
is built in to the motherboard. Remember XP does not support RAID natively,
so all configuration/setup has to be done with the utilities supplied by the
manufacturer from outside XP. Some, mostly old outdate RAID cards, required
you to open up the box, disconnect cables and set jumpers when you want to
break the mirror and boot from the mirror drive, but today, I believe most
of this is done with utilities on floppy or via the RAID card's BIOS.

--

Star Fleet Admiral Q @ your Service!

http://www.google.com
Google is your "Friend"

 

[Guest]

Thanks for your very helpful advice. The RAID controller is motherboard
based, (AOPEN AX4SPE Max II), so I am sure all those functions will be there.
Bye for now. David.

 

[Leythos]

The problem with using RAID 1 for backup is that your backup is
stored within the computer. It therefore leaves you susceptible
to simultaneous loss of the original and backup to many of the
most common dangers: severe power glitches, nearby lightning
strikes, virus attacks, even theft of the computer.

The real problem is that people, for some reason, seem to think that
RAID is a backup method/solution. It's for hardware redundancy only, and
performance issues too.

RAID does not contain the word BACKUP anywhere in the definition.

 

[Ken Blake]

In

The real problem is that people, for some reason, seem to think
that
RAID is a backup method/solution. It's for hardware redundancy
only,

Yes, that was the point I was trying to make.