Mirror and striped partitions on two disks possible?

[Organground]

Hi, when I got my PC I specified two 1TB hard drives in RAID0 configuration. I'm running a special software application that on startup requires reading from the harddisk to RAM of vast amounts of data so I needed to optimise read times and couldn't afford two), let alone one, SSDs. Read times were fantastic. Then I got nervous about data loss and so reinstalled everything, this time in RAID1. Result - the software has slowed down and loads at about a third of the RAID0 speed which is unacceptable.

So what I'm thinking is, ideally without having to reinstall Windows, and using just the two 7200rpm hard disks that as I say are presently configured as one 1TB RAID1 drive, can I
(1) partition the existing 1TB C drive into say an 800GB C drive and a 200GB D drive, and then
(2) convert the 200GB D drive (which will be mirrored across the two physical hard drives) into a 400GB RAID0 drive?
That way I could put the temporary files that need loading onto the 400GB RAID0 D-drive whilst benefiting from the stability and redundancy of having all critical files on the 800GB RAID1 C-drive.

Is this possible? Has anyone ever tried it? I should add that I have installed the Intel Rapid Storage Technology program if that makes any difference to its "do-ability".

 

[Karnor00]

In theory, assuming data is optimised under either setup, Raid 0 can only be twice as fast as Raid 1.

When you changed your setup from Raid 0 to Raid 1 did you reformat & reinstall everything or at least defragment your drives? The way the data is stored on the HDD under a Raid 0 setup is very sub-optimal if you switch to a Raid 1 setup (or if you simply turn off the Raid 0 setup). If you didn't clear both HDD's or at least defragment then the data could be spread over your drives in a very sub-optimal way, resulting in a very poor performance.

As to whether you can setup just a partitition of the HDD for Raid 0, I think this will depend whether you are setting up your Raid system via software or hardware. If its software then it should be possible, if hardware then typically you can only setup the whole HDD as Raid.

Finally, I would point out that a Raid 1 setup should not be regarded as a good way of backing up data. It will only protect you from mechanical breakdown of a single HDD. It won't offer protection from theft, fire, power surge, viruses to name just a few potential sources of data loss. There's nothing inherently risky about a Raid 0 setup provided you have proper backup systems in place.

 

[Organground]

In theory, assuming data is optimised under either setup, Raid 0 can only be twice as fast as Raid 1.

When you changed your setup from Raid 0 to Raid 1 did you reformat & reinstall everything or at least defragment your drives? The way the data is stored on the HDD under a Raid 0 setup is very sub-optimal if you switch to a Raid 1 setup (or if you simply turn off the Raid 0 setup). If you didn't clear both HDD's or at least defragment then the data could be spread over your drives in a very sub-optimal way, resulting in a very poor performance.

.....

Finally, I would point out that a Raid 1 setup should not be regarded as a good way of backing up data. It will only protect you from mechanical breakdown of a single HDD. It won't offer protection from theft, fire, power surge, viruses to name just a few potential sources of data loss. There's nothing inherently risky about a Raid 0 setup provided you have proper backup systems in place.

Thanks for the advice - yes I first of all configured RAID0 in BIOS and installed Windows and all software onto that; when I started getting itchy about data loss I changed the BIOS settings to RAID1 - which wiped the disks - and reinstalled Windows etc. The software I'm running was about three times faster to load into RAM when run from RAID0 rather than RAID1 (around 70 seconds compared to 3 1/2 minutes). Before going to the trouble of reinstalling Windows and everything again I thought it might be worth seeing what effect running two partitions, one RAID0 and the other RAID1, from the same pair of harddrives, if that was possible.

Couple of questions remain for me. Firstly, before doing anything I was planning to clone my disk in case I b*ggr@red anything up, and so that if I couldn't get the partition pair option to work, I could go straight to RAID0 without having to reinstall Windows. I've installed Intel rapid storage technology, which obviously is set for RAID1 at present, if I cloned the RAID1 drive and installed the clone (which contains RAID1 settings) onto RAID0, would that confuse the RAID? Secondly, to make my drives RAID1 or RAID0 until now, I've had to go into a BIOS setting before bootup, then I've installed Windows. Does that mean by definition I'm using hardware RAID or software RAID? Is it possible to use the Intel rapid storage thingy to convert a RAID1 partition into a RAID0 partition or would I have to do that in BIOS (which I'd rather not do if there's another way since I don't want to convert the wrong partition to RAID0 otherwise I'll wipe all my existing data...)