Is it possible? Two Raid 10 Arrays using two sets of four drives? PERC6i

It probably seems like a silly question but believe it or not I have never configured a perc controller. So I just need to verify that my configuration will work.

Thanks!

It will support two raid 10s.

There is no such thing as parity in raid 10, just lost capacity due to mirroring.

With raid 10, you get much higher throughput due to faster reads, as reads are taken from multiple drives at the same time; which stripe the data is read from dependent upon which mirror pair is nearest the data needed.  In the following link compare the results for the Dell 5e (bit old, but relevant) as a raid 1 and a raid 10 (4 drives)  using Fujitsu max3036rc drives

http://tweakers.net/benchdb/test/86.

Perhaps a faster setup overall would be to use a raid 1 of two disks and a 6 drive raid 10, but that depends on the servers use.

I don't believe the PERC 6 will support two RAID 1+0's only a RAID 1 and a RAID 1+0.  Better check with your team.

I'm curious as to why you are building RAID 1+0 out of these drives.  The parity penalty of 50% seems very steep for what would be pretty minimal disk IO advantage.  Especially given the cache on this PERC card and the lower RPM of the 146 GB drives on the 8x backplane.

In my 40+ PowerEdge servers I get screaming fast IO out of RAID 1 for OS LUNs. 

What are these LUNs going to be used for?  Maybe there is a better way to configure.

I did think of using raid 1 on two disks then raid 10 on four but since I didn't mind the costs for two more disks, two raid 10's seemed the best choice.

It will be for a dedicated Exchange 2007 SP1 server on Windows 2008. System and logs on the first virtual disk and the database on the second.

I know, crazy, Windows 2008, but given few factors, that's the way I had to go.

PsKeem....

From my playing with 2008, I love it. Feed it ram. Have a client with a 2900III just waiting for the release of 2008 retail....for now I have the Eval on it for testing. 

As per your raid setup, if all my clients had the resources I would have EXACTLY the same array setup as you propose.. will be super fast. Write back enabled should produce more throughput... it does on a Perc 6I I just tested on a raid 1 with 73 Gig 15k SAS drives. You might benchmark with two pagefiles... normal size on the system array, smaller one on the other array...sometimes it speeds it up a bit.

If you have the extra resources for a cold spares, I would keep them on hand (purchased retail, not OEM), sort of an investment, as 4 years from now, drive replacement cost will more than double...I have replaced drives in arrays which are 6 years old, where the drive cost more than triples the original.

Enjoy

If this was a general use server, not an Exchange (or dedicated SQL/database) server, I might go a 2 disk raid 1 and a 6 disk raid 10; not sure, as a 4 disk raid 10 is a sweet spot, a 6 drive array's throughput increase might not warrant the extra drive's cost, unless extra disk space would be the main criteria. 

Agree with pcmeiners totally.  Since this is an Exchange server then most definitely RAID 1+0 are the way to go.

I have an active/passive Exchange 2007 cluster for the Mailbox roles with two 8 spindle raid 1+0 luns on a CX3-80 for the DB's and logs. 

Thanks for the tip on the cold spares. I think I'll get at least one once I have the thing running.

It's funny, I purchased the drive configuration above and any raid configuration that would get the order through. Dell couldn't handle the different drives for whateverreason and they upgraded all the 73GB drives to 146GB to get the system through. At no cost. Sweet. So even one spare should get me through for a while.

I think I like Windows 2008 as well. I had the eval version setup in a simple test environment using VMWare on my desktop. It will take a little getting used to but I do like it. I have left myself plenty of room to add ram as well.

Also, thanks for confirming that I picked a good setup for my new exchange server. I will get started once the server is delivered. If I have any raid issues I'll post back here.

Definitely sweet.

What scary about 2008 is the number of changes you can make. :smileyhappy: