Some RAID questions

[TheMajor]

I have some simple questions about RAID.

1. If I install XP on a RAID0 array with 2 disks, can I just do a repair install without loosing the data (in case XP doesn't boot anymore)? I read that if you create a RAID array all data is lost, can the XP install "import" the array without having to create a new one? Like when using a single disk, you can just re-install XP without formatting and keep the data.

2. Can RAID0 be configured to use more than 2 disks (to make it even faster)?

3. If I have a system with XP on its own non-RAID disk + 2 other disks which are part of a RAID array, will I be able to just "enable" that RAID array after installing a fresh copy of XP, without loosing anything?

4. Do I need software to be running all the time, "managing the raid", or do I just need it once, to set it up, and install the drivers?

5. If 3. is possible and 4. is true, I guess I just have to re-install the RAID software/drivers to re-enable the RAID array?

 

[mBernhardt]

RAID of any sort requires at least 3 disks. I'm not sure what the top limit without looking it up. But it can go up quite a bit I believe.

I'm not 100% on this one, but I believe creating the RAID Array will wipe out any data on disks you are adding to the Array. I believe it first has to create the RAID structure and then format the filesystem on top of that. If you could backup your XP partition to another source I'm sure you could restore it after with no problem.

Windows XP (Profession at least I would imagine) can handle the RAID management.

Google would certainly be your friend for setting this all up.


If you do only have 2 disks you could setup a spanned volume across 2 disks. (Or stripped, or several different options) The main advantage with RAID is the redundancy, which of course isn't present with RAID0.

 

[TheMajor]

Thanks for your reply. but I was wondering about an onboard (SATA) RAID controller, not the Windows Dynamic Disk feature.

 

[mBernhardt]

Then I believe the onboard controller would handle the array and Windows wouldn't know anything about it.

If the first disk is already setup with RAID you may be able to add volumes without destroying the filesystem then just expand the filesystem to span all volumes.

 

[EricB]

I wouldn't do raid 0. that the hdd killer. it makes the drives half as reliable for twice the speed (in reality you only get a 50 percent increase)

 

[TheMajor]

I wouldn't do raid 0. that the hdd killer. it makes the drives half as reliable for twice the speed (in reality you only get a 50 percent increase)

Yes, I know; in reality you get less than half the reliability, the drives can fail, and the array could get messed up or something.

Is there anybody on these forums who is using RAID?

 

[veg1992]

i use raid 5, the most secure type of RAID there is, it requires 3 hard drives of the same capacity, but performance increases too

 

[MrCoffee]

You can RAID 0 ad many disks as you can physically attach and the performance does scale up with the number of disks (I've seen 8 disk in RAID 0).

Creating a RAID array destroys data present on the disks in the array.

RAID 10 is the best performance/reliability bu you need 4 Drives, RAID 5 is good for redundancy BUT the write speed on all but the most expensive controller cards is awful, simply awful. Personally I say go RAID 0 if you can only afford 2 drives (but backup your stuff) and if you can afford 4 drives go RAID 10. If you have a large server with many drives and an expensive hotswap RAID controller then RAID 5 looks good.

If you are using Hardware RAID, I.e. you have a controller card (or onboard) then you dont need software to "handle" the RAID bar the RAID driver. If you're using windows dynamic disks to RAID then you're very unfortunate and personally I wouldn't go there except perhaps with SCSI disks in a server.

@ question 3, if I understand you correctly then yes. However if you mean to incorporate the 3rd disk into the array then you will lose your windows install.

 

[TheMajor]

I'm planning to buy some additional hard disks. If I buy them, I would have 320GBSATA+320GBSATA+320GBSATA+300GBIDE+160GBIDE(external). Total: 1420 GB.

Say, I would copy data1 to data2, and backups1 and backups2 manually (with SecondCopy software), and I would configure the third and last 320GB SATA disks in RAID 1, and use SecondCopy again to copy backups3 to my external 160GB disk, I would have a fairly secure system right?

Any other suggestions, that will result in a more automated process? (less usage of SecondCopy to handle the mirroring).

I am not sure if the Asus P5W DH Deluxe motherboard wich I ordered can support 1x IDE disk and 1x SATA disk in RAID1. Probably not cause they would be on seperate controllers. I could solve this by getting another 320GB disk, but people will say I am wasting money, lol.

The page file should be on Data3 btw.

Maybe I could put the XP partition in a RAID0 spanned across 2 partitions on disk 1 and disk 2 (if both were SATA disks ofcourse). Or is it only possible to RAID complete disks for the OS?

EDIT: Data1 and Data2 are identical. Data3 and Data4 are identical. All Backups partitions contain the same data as well.

 

[TheMajor]

EDIT: Does somebody know the answer to my first question (first post)? If that is not possible, RAID0 would be useless.

There's another option. Wich would be more expensive.

I could get this:
2x 80GB SATA
3x 320GB SATA
About € 315 total.

Already have these:
300GB IDE
160GB IDE

This would be great I think:

80 + 80 in RAID0 (only windows XP)

320 + 320 in RAID1 (data1, backups1)

320 + 300 mirrored with SecondCopy (20GB reserved for page file, data2, backups2)

160 external, mirrored with SecondCopy (backups3)

This solution would be less complicated. I don't know if my case will support 6 disks, though (TT Soprano). But I could always use the 5.25 bays.

Total: 1580 GB (1543 GiB) of wich 800GB (781GiB) can be used as primary storage.

My previous idea would only have 620GB of primary storage, but my backups would be copied across 4 disks instead of 3 disks.