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RAID 5 and 1 configuration

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by tech_asher

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I have a few servers that I?m working on, the only problem is that the people that were here before for me configured the RAID arrays on the servers wrong, I have HP ProLiant DL380 G3 server, with RAID 5 and RAID 1.

I have 2 servers that are clustered together, that are running RAID 1, I want to break that RAID and remove the one of the hard drives.

The other server is running RAID 5, I want to remove the larger hard drive and replace it with hard drive the same size as the other ones.

The last server is also running RAID 5, but it has 4 - 36 GB hard drive and 1 72 GB hard drives I would like to remove 1 36 GB hard drive and the 72 GB.

So basically I want to break apart RAID 1 and reconfigure my RAID 5, I?m not sure if I can do that, thanks for your help. :)

17 replies

by shasca

Are wanting to do this without loss of data?

by tech_asher

No i dont want to lose any data. like i said im going to be pulling the hard drives from the OS array.

by shasca

Make sure your disaster recovery plan is up and running with a verified backup of all the data. Very vicarious project yer undertaking here.

Let us know. We are hoping for the best case scenario for you.

by normh3

If these are hardware RAID, I would check and see if the RAID utility for your hardware is installed and use it to reconfigure your RAID groups. If it isn't installed, you will need to locate it and install it first. You may also be able to do this via the configuration tool available to you during POST, but the servers will be offline to users if you decide this option.

One other possiblility would be to image your individual virtual disks using tools like Acronis or GHOST. Reconfigure the RAID cards using the BIOS utility and then restore the images back.
I am partial to the first suggestion myself.

by tech_asher

The software is installed on the server but it will not allow me to reconfigure the RAID, how ever i have not tried the tool in the POST and it does not matter if the servers are done, i will problem end up doing it after hours.

by cmiller5400

I have seen RAID array's puke when a drive has failed, even though "it should work."

Always have a Ghost or Acronis backup to revert to if the array does funky things. Theoretically, you should be able to pull the larger drive and insert a matched drive for the other size.

As far as reconfiguring RAID5 arrays and subtracting drives, it is usually data destructive. Backup your data, verify the backup is good, back it up again(never hurts to be too careful especially if the data is very important), then delete the config and start over.

by churdoo

Are any of the disks in any of the arrays hot spares or are they all member disks? It is odd that those 72-giggers are in there; the only thing I can think of is that original 36GB drives failed out of warranty (G3 has been around awhile) and they purchased the more readily available 72-giggers to replace failed disks.

For the 2 servers, clustered, RAID 1 -- I don't think you can do this as I don't think that RAID controller supports running a single disk not in an array. And even if the controller does support this, I don't think you'd be able do to this without destroying the contents of the arrays, so you'd have to back up, reconfigure, restore. You can confirm this by calling HP support.

For the RAID 5, removing a larger HDD and replacing it with same size HDD as the rest of the array -- if the array is Optimum status, then you can do this, and you can do it HOT. Confirm via the ACU that the array is optimum and if so, simply remove the one drive, wait a few seconds for the controller to detect the missing disk, and put in the replacement disk. Rebuild should start on the replacement disk automatically; confirm this with the ACU.

Your last server with RAID 5 of 4x36GB plus 1x72GB HDD -- Are you suggesting that you want to REDUCE a 5-disk array to 3-disks (and therefore reduce capacity)? You cannot do this. For this you would have to back up the content, destroy the 5-disk array, create a new 3-disk array (this would be reduced capacity, only ~65GB versus the ~130GB 5-disk array), and restore the content. Even if you don't need the capacity, it's available for growth, and the 5-disk array probably performs a little faster than a 3-disk array.

by tech_asher

NO there is not a hot spare on any of these arrays, they can be changed hot.

I have removed a RAID 1, on desktop systems in the office, but the hard drive ended up quitting on me, and I had to ghost it, I would like to do just pull out the 72Gb drive and replace it, but to do that id need to break the RAID 1 to get the Hard drives for that....

For the last server, I want to reduce to 3 drives in the array because the server isn?t a MCS, and I end the space on other servers, I?m trying to do this with out having to rebuild all the servers and the domain.

As for the array being odd with 72GB and 36GB, I?m not the one how set them up, but I?m the one trying to get the server running the way they should....

by churdoo

I understand you've removed RAID1 from desktops, not the same on the DL380 G3. And I thought when reading your original post that you wanted the disks from the 2x RAID 1's to use as the replacements elsewhere.

Please double-check me by calling HP Support, like I said, I don't "think" the DL380 G3 RAID controller will support running a single disk without an array (I've seen Dell RAID controllers do this, but I haven't seen HP do this, though I've never tried). Of course there's nothing stopping you from just removing a disk from those RAID 1's, silencing the alarm, and letting it run with the single disk -- except of course that that's hokey and your IT friends will make fun of you!

And I also want to re-iterate what other posters to this thread have cautioned -- make sure your backups are good!

If it's one of these servers with the RAID5 that you're trying to increase, then you "can", one by one, allowing array rebuild and return to Optimum status between disk swaps, put the 72-giggers in the same array, the array you ultimately want to increase, then buy more matching 72GB disks to complete the array, and once all of the 36GB disks in a single array have been replaced with 72GB disks, you'll be able to EXTEND the array to take up the additional capacity and DISKPART the NTFS Volume(s) it contains.

by tech_asher

Well yeah I want to remove drives from the RAID 1 servers and put them into another server for storage space for backups, yes I do have back ups running, I just need to move some services to a bigger server, the goal down the road is to get everything running RAID 5, but until I can get the Hard drives in to do that do what I can.

Id rather not kill the RAID 1 servers so I?m thinking it might be best not the change that right now. I would like to have one size on all the Arrays, but there are to many different sized drives around n not enough to make enough arrays to have them all the same.

I have a spare server right now with 2 36GB hard drives, if I took one out and replaced the 72GB drive in one of the RAID 5 server would that work? or I?m changing to size of the array? This server is the one that I want to have the bigger RAID 5 array on that?s why I want the 72GB drives from the other servers?..

by cmiller5400

Your array will be as large as the smallest disk for RAID1. Theoretically, you should be able to pop out the 76GB drive and put in a 36GB as long as the other drive in the array is 36GB.

by tech_asher

that would be nice if it was the RAID 1 arrays hard different sized drives, but its the RAID 5 arrays that do.... and if i try and replace the 72GB drive with a 36GB drive it will break wont it?

by churdoo

Does this spare server with the 2x 36GB drives have O/S loaded and ready to add production services to?

Again, with disclaimer about backups, you can swap 1 of the 36GB disks from that spare server with one of the 72GB disks, and in the ACU, make sure each of the arrays goes into rebuild. When the rebuild completes on both servers, then you can swap the other 36GB disk with the other 72GB disk in the other server, and confirm the rebuild again via the ACU.

You should be able to do all of this HOT and without breaking any arrays or losing any data. Now you'll have both of the 72GB's in your spare server and will just need one more 72GB to make a ~130GB RAID 5.

I just want to comment on this statement you made: "the goal down the road is to get everything running RAID 5"

Everything RAID 5 is not necessarily the best arrangement. Some things actually run better on RAID 1 or 1+0. Some will typically make O/S volumes and volumes containing database logfiles RAID 1 or 1+0, and general file data and database data files on RAID 5 volumes. Either one has redundancy so it's a matter of matching performance to the type of data being accessed.

by tech_asher

I did a ghost of my spare server O/S, restored it back to the RAID 5 I had running on it to make sure it worked, then reconfigured the RAID 5 to RAID 1, then pulled out on of the hard drives, with the servers off, when I booted the server, I got an error but it will worked just fine. I?m kind of happy about that. I replaced the hard drive HOT and it started rebuilding the array right away, happy about that too :)

So now I just have to figure out what I?m going to do to get the servers the way I want them.

I want RAID 5 on all my servers because they only have the O/S and Oracle programs, all the data is on a RAID cluster device.

by churdoo

If I understand correctly, your RAID 5 is mostly 36GB disks and one 72GB. The array can only use the equivalent of the smallest disk in the raid-set, so you can indeed replace the 72GB with a 36GB no problem.

by tech_asher

Ok that?s good; I just need to do a backup of the server and then just change out the drive. I hope that will work....

And for the RAID 1 I?m just going to have to wait until I get more drives.... or is there anything else you guys can suggest for me to try?

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