RAID newbie Q's

[Kruzin]

OK....so I aquired another used HDD, giving me 3 total. (1)WD 40 gig, (1)WD 20 gig, (1) Seagate 40 gig. All 7200rpm, ATA100.
So I figure it's time to mess with that highpoint RAID controller on my mobo. I uninstall anything I don't need, backup this-n-that, cram my essentials on one 40 gig drive.
Leave that as my boot drive on IDE-0.
Hook the other 40gig and 20gig each to their own RAID channel. Highpoint BIOS and Windows Highpoint software mngr see both drives.
I create a RAID0 array with these 2 drives.
Creation seems to go well.
But all I seem to be able to see in Windows is the 40gig. Windows Disk Mngr shows a "simple, dynamic" drive, which I have formatted NTFS, but it's only 37gig (what I would expect to show for a 40gig). I can't see the 20gig drive anywhere, 'cept the highpoint software, which tells me it's part of raid array 0_0.

What am I missing here? Why can't I access that 20gig drive?

[LvR]

Striped Raid perhaps.........?

If so, then you will only see 20 G off the 40G to pair it up with the 20G on the other channel - ie 40G in total - ie you will be waisting 20G.

What you need to do is to set it up as a JBOD (just a bunch of disks) or non-Striped raid.

[Wombat]

RAID-0 has to have drives of matching size, or partitions of matching size at least. So, you are seeing the 20GB drive. Unfortunately, you're only seeing 1/2 of the 40GB it's paired with.

That's my guess anyway.

[Kruzin]

OK..think I get it.
thanks guys
setting it up as JBOD gave me access to the full 60 gig of drive space.

[Dr Mordrid]

A 2 drive RAID0 gives additive capacity (eg: 2-40 gig drives gives you an 80 gig RAID0 array) with approximately twice the speed of a single HDD. Adding a third HDD adds about another 50% of a single drives speed and in this example another 40g of capacity. Adding a fourth HDD typicallly adds no speed but does add another 40g of capacity.

In RAID0 there is no data redundency so if you want the data to be backed up in realtime you have two other options:

Mirrored RAID0 (aka: RAID0+1): in this case you would have 4 drives set up as two RAID0 arrays, one of which will be a copy of the first that is made in realtime.

RAID5: in this case you need at least 3 HDD's, but you will only have the capacity of two of them. The space equivalent of one drive will be used for parity data. Parity data can be used to reconstruct the contents of a failed HDD once a new one is swapped in.

RAID primer: http://www.baydel.com/tutorial.html

Dr. Mordrid