Confused about RAID

[timtim86]

Hello people,

At the minute i have a 250gb seagate that i use as my data drive, and a 120gb seagate that I use as the system disk. My parents need a new HDD, so i was going to give them the 120gb Seagate and buy myself another 250gb seagate. My questions is - I have all my media on the bigger drive, so i don't lose anything if i have to reinstall, so is there any way of doing this with RAID? And, be honest, would RAID make any difference to me at all? I'd really like to not lose all my videos just cos i have to reinstall windows!

Sorry if i sound stupid,

Tim

[dangel]

If you're thinking of striping (where both drives are seen as one big drive) then no, you can't keep the data on the drive as when you create the new RAID set it'll effectively wax all the data. You'll also need to reinstall Windows and feed it RAID driver (the F6 floppy disk method/or slipstreamed drivers onto the installation CD). Striped RAID is much faster than a single drive for me with an XP installation taking less than 10 minutes. This is known as RAID 0.

If you're setting up a mirrored RAID (where one drive contains a clone of the other) then I suspect the same is true - that creating the RAID set wipes drive (in effect not physically). In this case you gain redundancy (i.e. if one drive fails your data is still there) but not any performance.

Is RAID worth it? Yup, 100% recommend striping - I wouldn't go back. It is worth backing up your important data (regardless of RAID) as a drive failure will mean everything is gone.

[timtim86]

That was a very informative post, thank you. Didn't realise that creating a RAID setup would wipe all the data. How would you go about backing up 100gigs of data? What about partitioning, how does that affect RAID?

[kalniel]

That was a very informative post, thank you. Didn't realise that creating a RAID setup would wipe all the data. How would you go about backing up 100gigs of data? What about partitioning, how does that affect RAID?

You back up 100gigs of data by deciding what you absolutely can't replace and just backing that up. 100 gigs is a lot! Or buy another hard disk for backups

Partitioning is a layer that goes on top of the volume layer (which is the layer that RAID works at). You sort out your volumes first, which is usually what people associate with physical disks, and then partition within the volume. With RAID you are effectively merging two or more volumes, so your computer will only see it as one volume, which can then be partitioned.

So the direct answer is partitioning doesn't affect RAID - RAID completely ignores it and works with whole physical disks, fancy matrix solutions aside

[dangel]

That was a very informative post, thank you. Didn't realise that creating a RAID setup would wipe all the data. How would you go about backing up 100gigs of data? What about partitioning, how does that affect RAID?

It's not that it physically wipes the data, it's that you basically creating a 'new drive' based on a number of physical drives. Windows sees the whole RAID set (composed of a number of physical drives) as one device - and so partitioning works in exactly the same way as far as windows is concerned. This is why you need to feed Windows RAID drivers - so that it can understand how to access the new device and boot from it.

Backing up - well you've basically two practical choices - buy a third drive to use on it's own for backups and put it directly in your PC or, use it externally with a USB2 case. I do the latter as you can turn off the drive when it's not in use.

There are other types of RAID too - see this: http://searchstorage.techtarget.com/...214332,00.html but it depends what your RAID device supports as to what you can use. Some forms of RAID require a lot of CPU interaction e.g. RAID 5 so aren't recommended without a dedicated RAID card (which has it's own processor) - e.g. if you were using a motherboard's RAID controller you'd find it's actually 'software' driven (e.g. NVRAID for nVidia chipsets) by your CPU. Personally I like the simplicity of RAID 0 which boosts performance significantly and couple this with backups using Acronis True Image which makes recovery a doddle.

Hard drives are so cheap now backing up 100gigs isn't a problem - not when a 300gb drive can be bought for silly money..

[timtim86]

Thank you for two brilliant posts, you've pretty much cleared it all up for me. Now i just have to decide how to backup everything and i'll be on my way! Does anyone else want to weigh in on Raid and how it's turned out for them?

Thanks Dangel.

[dangel]

No worries glad to help

I thought it'd be a lot harder the first time I did it - once you break your RAID virginity everything will be fine