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RAID0 - 4 640GB Drives - 2TB Limit

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June 25, 2009 1:52:19 PM

I have this motherboard: GIGABYTE GA-EX58-UD3R LGA 1366 Intel X58 ATX Intel Motherboard



I have the OS (winXP - 32 bit) on an OCZ Vertex Series OCZSSD2-1VTX120G 2.5" 120GB SATA II MLC Internal Solid state disk (SSD).

I have 2 1TB Western Digital Caviar Black drives setup in RAID1 for important files and backups of my SSD C: drive.

I am adding 4 640gb Western Digital Caviar Black drives. I would like to set them up in Raid 0.

My question is:

Obviously, 4x640gb is greater than the 2TB limit of XP (32 bit). But when I set up the array in bios, can I just set the size to 500gb instead of 640gb?

These drives will only be used for games, so redundancy is not a concern.

Thank you,


South Bridge:

1. 6 x SATA 3Gb/s connectors (SATA2_0, SATA2_1, SATA2_2, SATA2_3, SATA2_4, SATA2_5) supporting up to 6 SATA 3Gb/s devices
2. Support for SATA RAID 0, RAID 1, RAID 5, and RAID 10

GIGABYTE SATA2 chip:

1. 1 x IDE connector supporting ATA-133/100/66/33 and up to 2 IDE devices
2. 2x SATA 3Gb/s connectors (GSATA2_0, GSATA2_1) supporting up to 2 SATA 3Gb/s devices
3. Support for SATA RAID 0, RAID 1 and JBOD
a c 127 G Storage
June 25, 2009 10:38:46 PM

First of all, you should know Windows XP creates partitions with a bad offset, which is something to consider when you are using an SSD for performance. Vista and Win7 do partition correctly.

The limit of 32-bit OS do apply to processor instructions, not directly to disk access. Win XP 32-bit SP1 and later supports 48-bit LBA, allowing higher than 128GiB/137GB volumes. To exceed 2TB, you need both 64-bit LBA support and support for GPT partitions. Windows XP does not support these. Windows may also not be able to boot from GPT partitions.

Check this page for more info on GPT:
http://www.microsoft.com/whdc/device/storage/GPT_FAQ.ms...
June 25, 2009 10:55:48 PM

well, you could always use a software RAID-0 with dynamic disks (or use 2 RAID-0's in the bios and then RAID-0 with dynamic disks afterwards)
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a b G Storage
June 26, 2009 3:28:01 AM

How many games are you planning on loading to those drives??? Games don't take up THAT much space!!
June 26, 2009 1:17:09 PM

No the drives will be nowhere near filled :p 

That's why I was thinking I could set up the array in bios as each disk being 500gb rather than 640gb. Wouldn't windows just see whatever I set the array up as?

Also, their was mention of making the 4 disks "dynamic" and then setting up the RAID via Windows. Would this still allow for the speed increase (software vs. hardware)?

Thank you,
June 28, 2009 3:38:04 AM

If you don't need the space, for simplicity go with your first plan. You'll lose 360GB: 640GB x 4 = ~2.56TB (physical size) - 2TiB/~2.2GB (Windows/MBR limit) = 360GB.

If your priority is performance, you'll get most of it by not using all the space anyway (effectively short-stroking a large RAID-0 array over those 4 drives), so the wasted 360GB should be noise. If you want to make use of that extra space, define another array.

You might also consider putting those 4 drives in RAID-10 (640GB x 4 / 2 = 1.28TB usable), especially if you don't need more than ~20% (~250GB) of space. That would give you improvement from effective short-stroking, and also increase IOPs.

That said, while you will likely show performance improvement using synthetic benchmarks, don't expect much of a real-world improvement vs. using a single larger or faster drive.
June 30, 2009 7:49:33 AM

^ I'd do the RAID-10 (or 1+0, whatever term you prefer) approach. Make sure to use 1+0 and not 0+1 if you can. RAID 1+0 is better because it creates stripes from a mirror set, not the other way around. If a drives in a RAID 0+1 array fail on both sides of the mirror, the whole thing is lost. But in a RAID 1+0 array, the system continues to run at full functionality, assuming no mirror loses all of it's drives.

Also, RAID 1+0 recovers faster since it only has to remirror the failed drive. RAID 0+1 has to remirror the whole failed set.
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