Re: RAIDING different size drives

David Brown wrote
Rod Speed wrote
David Brown wrote
Sydney Lambe wrote

I want to mirror 2 disks mirror using RAID.

Can this be done on a 750GB and 500GB disk?

It's a single user desktop running XP with RAID provided by a PCI
card. Might change the mobo to one with RIAD if it's better?

This is for editing audio. Don't want to lose audio work if a disk fails so RAID looks right.

I believe that with a hardware RAID solution (and I think that also
applies to pretend hardware RAID that is often supported by
motherboards and cheap cards), you have to use whole disks in the
RAID. That means the 750 GB disk will be treated as 500 GB to make
the mirroring work.

Yes, but not all of them will handle that pair.

Fair enough - I don't have much experience with hardware raid cards, so I don't know the details of their
capabilities.

If you use software raid, you can do it on a partition level - use
250GB of the 750 GB for the OS, software, swap, etc., and use a 500
GB partition for mirroring with a matching partition on the other disk.

Of course, the idea of software RAID on windows to improve reliability is an oxymoron.

Wrong.

It would have been more accurate of me to say "on a windows desktop".

Still wrong. You do get extra protection against a hard drive failure.

This is perhaps not the group for discussing OS reliability,

Its fine for that.

but from my own experience (running IT for a small company for many years)

Mine leaves yours for dead.

and from endless accounts on the web, windows is generally an inferior choice of OS for solid and reliable storage.

Irrelevant to that silly claim that RAID 1 gains you nothing with Win.

And it isnt even an oxymoron either.

Factors that improve the reliability (regardless of the OS) are better hardware (desktops are typically fast but
poorer reliability),

Thats just plain wrong too.

server usage rather than desktop usage (fewer programs, with more limited scope and more testing), higher security
(avoiding malware or attacks), and better environment (such as UPS for power, cooled server room, no spilled coffee,
etc.)

Waffle.

RAID 1 does give better protection against hard drive failure even with Win.

You don't store files on a windows desktop and expect it to be "reliable".

Irrelevant to whether RAID 1 is more reliable than not using RAID 1 or mirroring.

You store your important files on a server (preferably on a non-Windows system).

No need to do that if you have adequate backups.

You keep good backups, whether you have a server or not.

And if you do that, you dont need a server.

If all you have is a windows desktop with typical usage patterns, then using raid, especially windows software raid,
is a such
minor step towards reliability that it's not worth considering until
you've looked at the system as a whole.

Irrelevant to your silly claim that mirroring adds nothing to reliability.

An external harddisk which you plug in, take backups, and unplug on a regular basis would do far more to protect the
safety of the data files than mirroring the internal hard disk.

Mirroring STILL improves reliability, most obviously
when a hard drive fails between backups.

Use RAID on a windows machine to improve speed, but if your data is important then save it regularly on a reliable
system.

Or use mirroring to improve the reliability.

File system corruption, due to Windows itself or to malware running
on the system, far outweighs the risk of hardware disk failures

Wrong.

I've seen a fair number of computers through the years,

I've seen a lot more than you have.

and I have very seldom seen physical hard disk failures.

Yes, but that doesnt alter the fact that they do fail.

I *have* seen plenty of corrupted disks,

I havent seen any more corrupted by Win than I have seen that have failed.

and I have helped out people with malware on many occasions.

No one ever said that mirroring helps with all problems.

Mirroring just means you have two copies of the corrupted file systems.

And helps when a hard drive fails.

I should of course have mentioned the biggest cause of data loss - user error.

Irrelevant to whether mirroring does help with hardware failure.

Again, mirroring is useless against this, while a good backup regime gives protection.

No one ever said that mirroring is a substitute for backups.

(though corruption may affect only some files, while hardware failure can affect the whole disk).

Mangled all over again.

And when Windows or malware mucks up your file system, your RAID 1
setup ensures that the same errors are copied over to the mirrored drive.

Just as true of any other OS.

Absolutely - and other OS's are not immune to either malware, attacks, or file system corruption.

And user error in spades.

But they are (assuming they are configured and administered properly) orders of magnitude lower risk.

Pig ignorant lie.

The same applies to server usage rather than desktop usage, regardless of OS - it hugely lowers your risks of malware
or corruption.

Irrelevant to whether mirroring does improve reliability.

In short, RAID can improve speed and/or uptime, but it does not noticeably improve data security,

Wrong.

and it is not a substitute for backups.

But does give added protection against the failure of a drive.

Yes, but hardware failure is such a tiny risk compared to everything
else, that it's not worth bothering about until everything else is in place.

Thats just plain wrong with everything except backups.

If you have two hard disks in a desktop machine and you want to improve reliability for your data files, you format
the second disk as a separate partition labelled "backups". You take regular copies of your data files from your
working disks into separate directories on the backup disk

There are much better ways to do backup than that.

(there are many ways to organise this, but that's a topic for another thread).

Nope.

This protects against user error, against most corruption (you are unlikely to corrupt the two independent file
systems), and gives reasonable protection against hardware failure (if your main drive dies, you'll have to re-install
your OS and software on a new disk, but your data is safe).

There are much better ways to do backup than that.

<reams of you trying to teach your granny to suck eggs flushed where it belongs>


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