How to recreate raid 5 array with larger drives?

Question

Here's my dilemna... In my Poweredge R530 I have a RAID 5 array made up of 6 300GB drives. We need more space so we want to create a new Array using 900GB drives, then copy the data from the old array to the new one. The problem is that I only have 2 available bays and RAID 5 requires a minimum of 3 drives. So what's my best option here? Some of the ideas I'm coming up with (not sure if these are viable or not:

1) Can I free up some space on the current array then remove one of the drives so I have 3 bays available to create the new array? Is it possible to reconfigure the existing array by removing a drive without losing data?

2) Can I create the new array as RAID 0 (only needs 2 drives). Then move the data from the old array to the new one and delete the original array (freeing up bays). Would it then be possible to add more drives to the new array and convert it to RAID 5 without losing data?

3) The option that should work would be to backup all my data from the old array. Delete it and remove the drives. Put the new larger drives in and create a new RAID 5 array, then restore from the backup?

I guess I should have planned for this by leaving at least 3 bays open, but I didn't think our data storage needs would grow so quickly that I didn't consider needing to have a new array with larger drives. Are any of the options viable? Are there any options that I haven't considered?

Thanks,

Chris

DELL-Chris H · Answer

ForMy808,

Out of the 3 you listed, #2 and 3 are the ones that will work. Where #3 would be the most labor intensive. With #2, the process you are referring to is called a Raid Level Migration (RLM), with RLM you would be able to perform any of the following migrations found on page 16. With creating a 2 drive raid 0 or 1 you can then transfer the info to the new raid 0 or 1 and then remove the original array, then RLM from the Raid 0 or 1 to the Raid 5 you desire. If you clarify the specific Raid controller you have installed I can provide you with a link to the procedure needed for that controller.

Let me know.

pcmeiners · Answer

#2 is good, but use cloning software or you will need to re-setup all drive security and re-install all software, ...a lot of work, a lot of unnecessary pressure.

#3 as much work as #2

Another option.........

With a software equal to Acronis ( as to cloning)......

Install large SATA drve as raid 0 or as standalone off mobo SATA interface (2-3Tb drive should do it) Clone present array to SATA previously described, startup server to insure it boots, shutdown. Remove present array with machine off. Install new drives, setup new array. reverse clone from SATA drive. You could have the new array up in a few hours, actual cloning takes up the most time. Before cloning run chkdsk on the old array, if chkdsk errors are present, cloned drive or array may fail or fail to boot,

Sure beats rebuilding from scratch, even if you have a backup.

formy808 · Answer

Thanks. I have a PowerEdge R520 with a PERC H310 controller.

formy808 · Answer

Can I do a Replace Member operation and replace each 300GB disk with a 900GB disk one at a time until all 6 disks are replaced with the larger capacity? Would this then increase the size of my array?

pcmeiners · Answer

You could but.....

1) do you realize how long this would take to replace 6 disks? this adds danger as this takes a lot of time with possible disk failures due to media errors.

2) it would not expand the original 300 Gig array size. You end up with a 300 Gig VD and a new VD would need to be created to use the remaining space of the new disks. Generally this is not practical.

DELL-Chris H · Answer

Also, and why it isn't practical, is that the additional spaces VD is not redundant to the original 300GB VD. So in the chance of a HDD failure, it can also come with corruption of the data. It isn't all that common, but is a possibility.

pcmeiners · Answer

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PowerEdge HDD/SCSI/RAID

How to recreate raid 5 array with larger drives?

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