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Converting from RAID 5 to Raid 1

Occasional Visitor

Converting from RAID 5 to Raid 1

hi there,


this is my first time posting into HP


I'm little bit fresh in dealing with servers and RAIDS


i have a live server that has 3x300 GB


i have created 2 logical drives and mistakly both of are raid 5


1 60 GB thats hosting the system and the 2 500 GB that has the data.


now my question is:

1- what is the best solution to overcome this with keeping my live system

2- is there a way to change to RAID 1 without lossing my data


thanks for your help guys inadvance


thx, MK

Respected Contributor

Re: Converting from RAID 5 to Raid 1

The quickest way you could do this is to add a 4th 300GB drive and then convert from RAID 5 to RAID 1+0 using all 4 disks.

Since you can't do RAID 1 with 3 disks, if you wanted to convert it you'd have to first shrink your logical drives to under 300GB in size and then I think you might have to convert to a RAID 0 first, then remove one of the drives from the array, and then go from RAID 0 to RAID 1.

Like I said, since RAID 1 isn't possible when there are 3 drives, you probably can't go directly from RAID 5 to RAID 1 and then remove the 3rd drive later.

If you did add a 4th hard drive though, you'd then be able to have one of the logical drives setup as RAID 5 and the other as RAID 1+0 if you wanted to. That way if you have something that's write-heavy, you could convert it's drive to RAID 1+0. The OS drive might be less write dependent and could be happy with RAID 5.

Plus, with 4 disks, you can go to RAID 1+0 without losing any total space, and it'll be faster than having a single pair of disks in RAID 1.
Valued Contributor

Re: Converting from RAID 5 to Raid 1

My question would be why?  What are you trying to accomplish?  With RAID 5 you have parity striping to keep your data alive in case one of them dies.  My recommendation would be to buy an additional drive as a hot spare.  That way, if one of your drives fails, the hot spare will be pulled in and re-striping will occur while you get the failed drive replaced.