BeyondTheCurve

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Aug 17, 2008
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I'm building up the following workstation:
Intel Matrix RAID (ICH9R) capable motherboard
6 matching SATA II hard drives for the RAID set(s)
1300 FSB
Intel Core2 Quad processor
UPS for autosave & graceful shutdown if power goes out
and I'm looking for opinions and rationale for chosing one of the following configurations. I'm looking for best performance with redundancy.

Option 1: create one RAID 10 set using all 6 hard disks, then partition it into two drives: one for OS & applications, the other for data

Option 2: create two RAID 5 sets with each using 3 hard disks with one RAID 5 set for the OS & applications and the other RAID 5 set for my data.
 
Option 1 would give you the best performance as the calculations are not as intense as those for raid 5. Option 1 will also give you the most redundancy as it could tolerate up to 3 HDD failures max where option 2 would allow only for 2 max. Go with option 1.
 

rockchalk

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Oct 9, 2007
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Intel's RAID stack does not support 6-disk RAID10, only 4-disk RAID10. That eliminates option 1.

Have you considered a RAID1 for your OS & Apps and then a 4-disk RAID5 for data? It eliminates the need for XOR calculations for your OS/Apps volume. I'd also expect that your data would be larger than your OS/ Apps.
 



I also recommend 2 drives for mirroring for the OS and 4 drives in raid 5.

Nice to see someone not falling into the raid 0 trap.
 

BeyondTheCurve

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Aug 17, 2008
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Please forgive my delay in saying "Thank you", but client deadlines have slowed the build of this system until now. I hadn't considered the mostly wasted XOR calculations on OS and apps, nor the idea of RAID 0 for OS/apps and RAID 10 or 5 for data. I do appreciate the suggestions and feedback. Having finally built the system and booted into the BIOS. Having read your comments, I have 2 new configurations to request your feedback on and a potential RAID 5 problem to ask about.

I just read an article saying that RAID 5 can return garbage under certain fault circumstances or be unable to rebuild the volume. has anyone heard of that problem with RAID 5?

The ICH9R chipset on the ASUS P5E WS motherboard does support 6 SATA drives according to the BIOS. Also, the motherboard comes with the Marvel SATA RAID controller, which gives me the option of adding a 7th and 8th drive to the system as either a single drive or RAID 0 volume for the Windows XP swap file. This offers the following additional configurations:

Option 3: Your suggestions of 2-disk RAID 0 for OS/apps and 4-disk RAID 5 or 10 for data.

Option 4: instead of using Windows to create OS/app and data partitions, on a single Matrix RAID 10 volume, create two 6-drive Matrix RAID 10 volumes so that the partitioning is done in Matrix RAID hardware. Would Matrix RAID reads/writes be faster if the OS/app and data disks were created and accessed via Matrix RAID or via Windows?

In summary, my questions are:
a. Is there a performance difference between: 1) a single 6-drive Matrix RAID 10 volume partitioned in Windows XP into a C: (OS & apps) drive and a D: (data) drive, and 2) two 6-drive Matrix RAID 10 volumes for C: and D: drives?

b. Is there a problem with RAID 5 redundancy

c. If not, does the ability of two 3-disk Matrix RAID 5 arrays to operate simultaneously on independent data streams outweigh the XOR calculation overhead? Would it perform better than Options 3 or 4?

I appreciate everyone's analysis and advice. Thank you.