Can I create a software raid 0 array without losing data?

[confusion]

Hey, i have a rather full 200gb hd and i'm in the market for a new drive. I'd like another 200gb, and throw the two together as a software raid0 array. The data on the drive isn't critical, its just things like movies and music and pictures... Anything sentimental or of other worth is going to be backed up to another drive on a regular basis. I'd go the raid5 route but i really cant afford the card nor the redundancy.

Anyway... i'd like to set this up _without_ losing the data on the current 200gb. I know nothing of raid so far, but before i started looking into it i thought i'd just ask... is it possible to 'expand' a current drive into a raid array including that drive? If not then im pretty screwed... will i have to buy an ass load of dvd's and backup to that first?

Either way, would it be possible to make the final array expandable such that at a later date if i get another 200gb i could just throw it in and just expand the drive without losing anything?

Any replies would be greatly appreciated.

Thanks a lot in advance guys,

John

[PCanavan]

With RAID you've got three basic options:

1) Hardware RAID
2) Hardware-assisted RAID
3) Software RAID

(1) is by far the best, but as far as I know is only supported by heavy-duty server cards, mainly SCSI, with price tags to match. It involves no direct software involvement, and completely virtualises the whole thing. Doesn't sound like this is what you want.

(2) is what most people who've got a "RAID card" really have, based upon various posts I've read. To save cost, some work is offloaded to the chipset, but some is done by the main CPU. You'd need to get a card which supported it, so it's also out based upon your post.

(3) does the whole thing in software. Instead of needing to work at a drive level, it can work at a partition level. So you could have one set of partitions mirrored, another set striped, another set with parity, and some partitions just running off one disk. All on the same set of disks. This comes with the kernel - you enable them under "RAID and LVM" (or similar - I'm on my work WinXP laptop just now).

So....

(3) would let you go RAID 5 for only some bits of your system, cutting down on the amount of overall redundancy. If that's really what you want then there's nothing to stop you; get a couple of smaller drives, parition, and set up an array over them. You should be aware that RAID 5 is somewhat well-known for the processing penalties, though; I've not run it, but on occasion I've not run it for that reason, after taking expert advice.

I don't think you can set up software raid without wiping the partitions (NB: not the whole drive, though...), but if you don't have to deal with the whole disk you could just create a holding area, tar and gzip, faff around, and then put it back. Or just stream it off to tape \ CDR \ DVDR \ whatever. Hardware RAID, and probably hardware-assisted, would let you just mirror an existing disk.

[eqlazer]

I wouldnt recommend raid-0, because if you loose one drive you loose all data. Why not just mount the new disc under /mnt/storage or something and move movies and music to it, and keep the old one as it is. Raid-0 sounds like it got more problems then its worth

[Genone]

[PCanavan]

[Genone]