RAID question

[Rob Chamberland]

I have a Compaq ML530 system with a SmartArray 3200 controller and the following hot pluggable RAID configuration:

Array A:
2x9.1 gb RAID 1+0 (holds the OS)
Array B:
2x9.1 gb RAID 1+0
Array C:
3x18.2gb RAID 5 (holds data)
Five slots empty.

A disk failed on Array C. We're considering buying 3 new 36+ gb disks for a fourth array using RAID 5.

The question: Can we create the 4th array, move the data there from array C, then convert array C to Raid 1+0, or do we need to replace the 18.2 disk to fully recover array C before we can do anything with it?

[KapilRaj]

i hv'nt worked on this product but logically,

as u hv raid 5 in Array C , u hv'nt lost any data hence u can access the data so u can either backup and then restore them on to Array D.

If this was me running hpux i would hv added the new lun's to the datavgh and did a pvmove..

Kaps

[Uwe Zessin]

Rob,
you should be able to access the data of the logical disk in disk array C, but I don't think you can 'convert' it to RAID 1+0.

I don't have direct experience with the 3200, but on all SmartArray controllers I have met so far they work like this:

you combine several physical disk drives to a 'disk array'. The 'disk array' has free space out of which you can create one or more 'logical disks'. The logical disks are then presented to the server.

A RAID-level like 1+0 or 5 is a characteristic of a logical disk, not the disk array. You can have a disk array that contains two logical disks of RAID 1+0 and another one of RAID-5.

So I am afraid you have to back up the data from disk array C, delete it and then re-create a new disk array with two physical disks drives. Then you create a new logical disk with RAID 1+0 within this new disk array.

[Rob Chamberland]

Thank you for your answers, but I'm afraid I had a different sort of issue in mind. Sorry if I wasn't clear.

Basically, array C is flagged as being in "recovery mode" because it has a bad disk. Can I reconfigure array C as RAID level 1+0 without having to plug in a replacement disk. Or do we absolutely need to add a replacement disk then fully recover the array before we can try reconfiguring it as RAID level 1+0.

I'm wondering if SmartArray (or the software) will not let anything be done to that particular array, let alone let it be reconfigured, until that "bad disk" flag has been cleared and it has been fully recovered.

[e4services]

Short Answer, No.

You need to recover the fail array first, before you can continue to change anything. Actually I do not think you can even add the new 4th array until you replace the drive.

What you CAN do is remove the failed drive, wait a minute and return it to the array. The controller will go off and try and recover the array now. If it fails again, you will have to replace it, but if it can recover, you may have enough time until it fails again to create the new array, move the data and then delete the 3rd array, and create the new mirror array you want.

I guess you could monkey around with copy of the data to dodge having to buy a $250 drive, but you would be putting yourself in harms way. Put in one of the 36GB, copy the data to it, remove the Array C, put back on 18, copy the data to it, remove the 36 and put all the 36s back where the 18s were,copy the data back,remove the 18,replace 2-18s.

[Rob Chamberland]

Thank you! That's what I thought. Actually, I wouldn't even need to try that (addmittedly cool) trick with switching the 18/36's because I have 5 free drive bays to fool around with. So I can create my new array on those, copy the data there, then keep the old 18's but reconfigure them later.

Excellent, thanks again.