RAID question

[hakonpca]

If I run a RAID 0 (two internal HD) and use an external backup drive will it or could it backup the RAID correctly?

I want to run RAID 0 for performace, I'd like the security of RAID 10 but don't want to have to buy 4 HD. Is it possible to run RAID 0 and use a backup external HD (as big as the combined RAID drives) and do a once-a-day backup (or whatever) for security? Or anything to that nature. I know that if one of the drives fails it wouldn't be automatic rebuild, like RAID 10 but at least my data would be safe on another HD, right?

 

[johngoodwin]

Short Version:
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Yes, your data is safe on another drive.

Long Version:
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1) A power surge/sag can still kill all your equipment at once
2) If you need your backup, you still may need to re-install Windows, and drivers to restore your backup if you didn't make bootable restore disks, or at least figure out how they work.
3) If you have to re-install Windows, and want to re-install onto a RAID 0, be sure to have your floppy with the RAID drivers someplace handy.
4) You may want to have an offsite backup, incase you get robbed, big power surge, lightning strike, fire, flood, or any other disaster which basically demolishes all your gear in one shot.

Hope this helps,

John

 

[hakonpca]

would an external backup HD see the RAID as just one drive and be a 'normal' backup or would I have to do anything special to get said backup to work

 

[nobly]

Windows sees the RAID as one drive. Windows sees your external backup HDD as one drive. No problem backing up data. Drag and drop, I say.

 

[bmouring]

Windows sees the RAID as one drive. Windows sees your external backup HDD as one drive. No problem backing up data. Drag and drop, I say.

Yes, I was going to point out that it is the OS that you have to worry about. Drag and drop would work for backing up all of the normal user and some system data, but for a really slick solution you could try one of any drive imaging solutions that support your RAID (presumable a Mobo-based "fake" or partial hardware RAID) to make an exact duplicate which, in the case of a failure, could be booted to get you up and running in minutes (if mobo supports booting from usb) I do something similar in my system.

 

[nobly]

Yeah, I mean, you could do that too, something like RAID 10 or 0+1. But in the OP, they didn't want to do that.

sidenote: I'm not sure if the below will work, so don't ask me if you try and it fails
I guess it would also be theoretically possible to get a HDD the same size as your RAID 0 array and have it copy 2 drive images to it... 1 for the 1st RAID drive, and 1 for the 2nd one. Or just drive image the entire RAID on there, when your system crashes, you can crack open the enclosure and stick the HDD in your computer!

 

[pat]

would an external backup HD see the RAID as just one drive and be a 'normal' backup or would I have to do anything special to get said backup to work

you don't backup hdd, you backup files. so, you take the file from th array to the backup drive..

 

[bmouring]

Or just drive image the entire RAID on there, when your system crashes, you can crack open the enclosure and stick the HDD in your computer!

That's exactly what I was getting at, I have a crontab weekly job to do just that, but there's no real need to crack open the enclosure, you should be able to simply modify the BIOS boot options and boot from the USB drive (again, if it's supported). If you check my sig, the 2x 74's get imaged to my 200gb and I have tested the bootability of the image, works fine for Windows and Linux (with some fstab changes).

As for your other suggestion, it sounds really cool, but I am unaware of any device or software that allows such a ... asymetrical 0+1 RAID?... setup, but it's a fine idea. Quick! patent it before Microsoft or IBM does!

 

[Codesmith]

There are two kinds of backups

1) File/Folder Backups used to backup and restore your documents.

2) Partition Backups used to backup and restore an OS.

RAID isn't a problem with the first type because you can backup and restore with windows running.

With partition backups you can backup with windows running, but to restore the your OS partition you need to boot from a rescue CD.

If the rescue CD can work with your RAID controller then you have no problem restoring your OS. If it doesn't then you are in trouble.

I use True Image for OS backups. The version 8 CD saw my RAID 1 as two indentical drives with working files systems and RAID 0 as two drives with gibberish.

The True Image 9 CD sees my RAID 1 as a RAID 1 array. I haven't tested it with RAID 0 yet as I prefer not to use RAID 0 and I haven't gotten arround to testing it out for curiosities sake.

---
So if all you care about is backing up your important files manually or with something like EMC Retropect 7.5 then you have no worries.

If you want to backup your OS so you never have to reinstall when disaster strikes then you will need to test to rescue CD to find out if it supports your RAID controller.

Even if it doesn't support your RAID controller you could probably back and restore if you did both from the boot CD. The software would backup gibberish from both drives then restore the same gibberish. But the image size would be equal to the full size of the hard drive as there is no recognizable file system to tell the backup software what sectors are in use.

Again you better test it out first.

 

[michaelahess]

I use ghost for this situation, I can take my raid 0 with 2x250gb's and ghost the image to one of my servers, if the computer crashes, I boot with a pxe image I have of ghost that has the proper raid drivers (that's the hardest part, finding them) then it dumps the image back on and boots like new. This will work with raid 0 or 1 on nvraid, I can use my highpoint 2320 drivers for my 4x320 raid 5 array and do it with those as well, but I don't since it's raid 5, though I tried it and it worked. Getting ghost to work with drivers is a real bitch with some things though, and I've had it work on some systems and not others even when the chipset was the same.