hardware raid setup

[livingsacrifice]

I have a server I'm working on that has 6 drives 2 setup in raid 1 and 4 in raid 5 (typical server setup) all in hardware raid mode. Question is, I want to add 2 drives do the raid 5 configuration is this possible without wiping the information contained on the drives?

 

[jtvang125]

Gotta start from scratch and all data in the array will be lost.

 

[MerlinRML]

It depends. The RAID controller must support 2 more drives and also capacity expansion of some form. Then you should be able to grow the RAID 5 array to the new disks and expand the file system or add a partition from there.

It would help to know specifics about the hardware to be able to give a firm answer.

 

[livingsacrifice]

It's a Dell PowerEdge 2950 server with an onboard perc 5 controller, all the drives are 2.5" SAS 146gb 10k it's got 6 in there right now and 2 more are going in there. Yes it has slots for them on the actual server so I would figure the raid card to be able to support it.

 

[Fullmetal Chocobo]

The Perc 5 RAID controllers can do capacity expansion and RAID level migration, but it is best to do so (in my experience with them anyway) to do it in the RAID BIOS, so the server will have to be taken offline. Also, it takes a while, as it has to completely rebuild the array. But it does keep the information intact.

EDIT: I would, of course, advise doing a backup of the data before attempting the process, just in case.

 

[Brovane]

Adding drives if you are using a SAN is not a problem. Using the RAID controller inside a server is much more tricker. Do you have a good backup method?

 

[pugh]

I second what Fullmetal said. Do it in the RAID BIOS. But be sure to back up your important data before proceeding.

 

[Rubycon]

I always image all logical drives/partitions contained in an array before doing anything drastic. That way if a drive throws an exception while expanding you don't get fired - if you're in that unfortunate position.

 

[RebateMonger]

Next question is:

What's faster?
a) Make backup, delete old array, add drive, create new array, restore data from backup.
b) Make backup, add drive, expand current array, allow array to rebuild.

 

[Brovane]

Originally posted by: RebateMonger
Next question is:

What's faster?
a) Make backup, delete old array, add drive, create new array, restore data from backup.
b) Make backup, add drive, expand current array, allow array to rebuild.

Normally the backplane speed of the hard drives should be faster than the restore speed of tape. However I have no idea what impact doing the option to expand the drive will have on drive speed. I would research the RAID controller documentation and find out if they have documentation on speeds of the array rebuild when you add additional disks.

 

[Fullmetal Chocobo]

Originally posted by: RebateMonger
Next question is:

What's faster?
a) Make backup, delete old array, add drive, create new array, restore data from backup.
b) Make backup, add drive, expand current array, allow array to rebuild.

Either way, you are going to have to build the new RAID 5 array. Converting is just about as fast as initializing a new array, so you are only adding steps if you delete the old array (#1).

I would: make backup, add physical drive, expand array. Expanding the array automatically rebuilds it. And if you do this outside of the RAID BIOS, it is possible that you will have to redo it if there is activity on the RAID array. Never again with I mess iwth a PERC controller outside of it's BIOS.