RAID configuration for Fibre Channel SAN

Knubje

Knubje

Knubje

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Hi All,

I have a quick question just wanted some advice.

I have a new Server, SAN and Fibre Channel Switch.


The SAN is going to be the home of VM's running on vSphere through the new server. The SAN is also going to store replica's of VM's for DR/Fail Over and probably copy them off to our other SAN too.


Question is, I am currently formatting the new SAN (4*1TB Drives) and I am in the school of thought that I should create a RAID10 array as I believe this gives the best redundancy/performance for what I want.

Can someone confirm this? Just want to make sure I don't waste time having to format it all later on...

In theory I should get around 2Tb of storage with the possibility of 2 drives failing as long as they are not from the same mirror pair?

Thanks!
 
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Personally, I would just make up a RAID 5 array with a hotspare. RAID 10 is a great way to waste disks and money IMO. Also, with a RAID 5 array, you can lose one disk, have it auto replaced with the hotspare and then lose another one (as long as the hot spare isn't still rebuilding). Performance would improve too.
 
rainbow6six said:
Personally, I would just make up a RAID 5 array with a hotspare. RAID 10 is a great way to waste disks and money IMO. Also, with a RAID 5 array, you can lose one disk, have it auto replaced with the hotspare and then lose another one (as long as the hot spare isn't still rebuilding). Performance would improve too.
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Thanks.

Overall the performance of RAID5 is the same as RAID10 then?

RAID5 would mean I get 3Tb of space with the spare drive as the 1Tb mirror drive right?
 
Knubje said:
Thanks.

Overall the performance of RAID5 is the same as RAID10 then?

RAID5 would mean I get 3Tb of space with the spare drive as the 1Tb mirror drive right?
Click to expand...

In you instance with 4 drives, performance would be better.

Nope, you would have 2TB of useable space, but thats the same as if you setup a RAID 10 array with 4 disks.

Ideally, if you an get more drives, your options improve slightly.
 
With RAID5 the usable capacity is (N-1) * capacity of smallest disk.

So in your case with 4 disks you could have 3TB of capacity. However, since RAID5 only has a fault tolerance of one disk, it is a good idea to have a hotspare as suggested. So, with a hot spare, you will have (3 -1)*1TB = 2TB + a hotspare.
 
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