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#247665 - 26/01/2005 21:52 Enabling software RAID5 on WinXP
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
A cool hack, for anyone running XP who wants to use RAID5. Apparently it shares disk drivers with WinServer, and by patching a few bytes in a few files, the latent RAID5 system can be enabled (complete with GUI).

The relevant how-to link is here.

Cheers

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#247666 - 26/01/2005 22:02 Re: Enabling software RAID5 on WinXP [Re: mlord]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Until WindowsUpdate replaces the hacked file and your RAID stops working?
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Tony Fabris

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#247667 - 27/01/2005 11:15 Re: Enabling software RAID5 on WinXP [Re: mlord]
drakino
carpal tunnel

Registered: 08/06/1999
Posts: 7868
Quote:
This screenshot shows the disk management window after detaching a hard drive and re-plugging the data cable after only some seconds. For safety reasons, Windows does not assimilate the drive into the array automatically. The other array members are indicated as 'failed redundancy'.


This is why I still really can't trust a software raid all that much. If I run a 24/7 server, I want it to be as redundant as possible 24/7. That means if a RAID issue occurs at 11pm, I don't want it to sit there waiting for me to decide how to fix it at 8am. Thats a 9 hour window where a second failure would nuke everything. I much prefer the RAID systems with enough intellegance at the hardware level to see a problem like what they did, and automaticially rebuild that drive. If it notices a trend, it then decides to remove the drive from the RAID and considers bringing on an online spare.

I guess I get spoiled at times working with some advanced storage solutions. But it really has opened my eyes to the cost of doing it cheep up front and paying for it in the long run, or paying just a bit more to have a solution that doesn't cost you more down the road.

And I agree with Tony here on the specific RAID 5 implementation in XP. It will work, up until the next MS patch. Usually other fixes hide inside the patches MS releases that people don't notice unless they spend 30 minutes reading about it. Big example I had to deal with, Windows NT 4 had a security rollup patch released after service pack 6. Now, service packs tend to include things like newer drivers and such. However, this rollup patch was seen as many as just a normal security update and little more. However, it started life as service pack 7, and still had bits of that, including (by the time of release) an out of date array driver. For about a good two months, a high volume of calls came in to my group about systems applying this patch and blue screening on reboot. Turns out the problem was the array driver in that patch was so old, it didn't know how to talk to the array hardware with newer firmware. It was fixable, but was a pain to recover from. I'd hate to have to do a similar procedure every few weeks on a machine I run.

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#247668 - 27/01/2005 15:02 Re: Enabling software RAID5 on WinXP [Re: drakino]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Quote:
This is why I still really can't trust a software raid all that much.


If by "software raid", you mean "MSWindows software raid", I'll agree. But the software raid under Solaris has as many features as any hardware RAID setup I've ever seen. It'll definitely automatically swap in a hot spare. It won't try a bad disk again, but I've never seen it label a disk as bad unless it really was bad, except when the cable got unplugged or something like that. And you can have as many hot spares set up as you want. And have them assigned to multiple RAID sets, so you can just have, say, two hot spares for five RAID sets and have them used appropriately.

All I'm saying is that you can't judge all software RAID based on one implementation.
_________________________
Bitt Faulk

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