Raid Migration (between controllers)

[jawpaul]

I am currently in the process of upgrading from RAID 0 to Raid 5.
The raid is for VIDEO storage and is nearly full. I do not boot from it.

My current setup is 2 x 500gb in a raid 0 done with the built motherboard RAID controller.

I am upgrading to 4 x 500gb in a raid 5 using a DELL Perc 5 E.
The Perc 5 E supports online raid level migration.

What is the best way to do this? Can I just plug my RAID 0 array up to my new controller and have it recognize it automatically then perform an ORLM?

John

 

[unhappy_mage]

No. The two controllers will have a different on-disk formats, and you could destroy your data that way.

Do you have six disks or four? If you have six (i.e., two old and four new) then create the new 4-disk raid 5 and copy everything over. If only four, I think you'll have to create a new 2-disk raid 0 on the Perc and copy everything over, then add the other two to that array.

In case it's not obvious, I would suggest having a current backup before you start this process.

 

[XS Janus]

I agree with unhappy_mage.
Don't risk it, it won't end happily.

If you don't have 4 new drives but only 2 you could also invest in one more and make RAID5 with 3 drives first. Then copy all your files and add the 2 old drives to the array and migrate.

One note: beware that that migration process will take a LONG time.
I timed my 3ware 9650SE at 3-4 MiB/s doing those kind of calculations.
and for 2TB array that will take an LONG time (5-6 days of constant hdd usage)
On top of that your performance is dismall during that process (~5MiB/s) and if any of your hdd fail during this procedure your data is f*ed!

All this is why I had to spill out more cash than initially planned and completely populate my 8 ports controller with 1TB drives other than only 4 I planed for a start.
But when I calculated that any additional hdd would take about a week or more to add to the array + increased risk of failure during and data loss in that stressful times, I quickly reconsidered.