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RAID Suggestions Please

 
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fpvdrif6
Occasional Contributor

RAID Suggestions Please

Hi all,

 

I have a DL380 G5 which I need to put into production soon.  It will be running Server 2008 R2.  I currently have 6x drives and 4x more are ordered and on their way.  They are 72GB SAS drives.  Server is running a Smart Array P400 controller with 512MB cache and BBWC.  All pass the Smart Start diagnostics except one drive fails the SMART test, it is predicted to fail soon.  So once my order arrives I will have 8x good drives inside the server and 1x for a cold spare.  I will confirm all is good again with more diagnostics once I have done this.

 

My real question is what RAID method should I use?  I am familiar with RAID and experienced with RAID 1, RAID 1 w/ hot spare, and RAID 5.  I am not experienced with RAID 6 or RAID 1+0, these are supported by the controller.

 

I have been reading online a number of different blogs and forums where RAID 5 failures have not been recovered due to URE encountered upon rebuild, RAID 6 sounds like it might work for me?  Or would RAID 1+0 work better for me (have 2x logical drives, I would prefer one though) and just keep an eye on failures and replace that cold spare ASAP?  I don't think I like this idea but if I can be convinced...

 

I would prefer a hot spare and to have as much room as possible in a single logical drive for the OS.

 

Have at it.  Thank you.

3 REPLIES 3
Mark Matthews
Respected Contributor
Solution

Re: RAID Suggestions Please

Here is a very good link to all the different RAID levels with diagrams and even the flow of the data if you click the diagrams!

Also good descriptions on advantages and disadvantages etc.

 

http://www.acnc.com/raid

 

It all depends how much useable space you want and how much of a risk you want to take really...

 

With RAID6 you 'lose' 2 disks worth of space but have the possibilty of 2 disks failing at the same time with no loss of data.

RAID 1+0 (or RAID 10) is basically a striped mirror. Not to be confused with RAID 0+1 which is a mirrored stripe, but I dont think you can do this on HP array controllers...

Thanks

Mark...


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Jan Soska
Honored Contributor

Re: RAID Suggestions Please

Hello,

as you plan to use serious sas drives (not sata) you should not by worry when using raid5 in 7+1 configuration. This gives you capacity of 7 drives and protection against one drive failure. Failure rate of such disks is really low and just use hw monitoring and replace drive in case of failure.

Of course, is you plan intensive random write, raid5 is not recomended.

 

Jan

fpvdrif6
Occasional Contributor

Re: RAID Suggestions Please

Thanks guys,

 

I ended up going with RAID 6 with a hot spare.  This gives me the benefit of 2 parity drives plus the hot spare and all up it was plenty enough space for the application.

 

32GB RAM and 2nd CPU kit upgrades and the server is flying nicely.

 

Thanks again.