Does Creating an Array Erase Disks???

[Dan Hawker]

Hi All,

Quick question regarding another problem I am experiencing.

If I create an array using the ACU and then make a Logical Volume, using disks from a different server, will the disks be erased in the process???

I've a drive that I'd like to move to another server but I need the data on it.

TIA

Dan

[Andrzej Kowalik]

YES, you lost your data.

regards,
Andrzej Kowalik

[Dan Hawker]

Hi Andrzej,

Thanks for the reply, thought as much when looking at the ACU, but thought something could be done. This seems rather stupid, after all its just a disk.

When a RAID 0 array fails, you add disks and bring it back up. Surely in this case (just a single disk is the entire Array) its just like having a degraded array.

Ah well, will investigate other methods.

Thanks

Dan

[Roy Main]

I'm not exactly sure what you're asking - in some scenarious you can move a drive with data on it to another server. You're Smart Array user guide covers these situations.

If the drive was the only one in an array and you moved it to another server - that server's SA controller would discover the new array and allow you access to it and the data.

However, if you were to move it AND reconfigure the drive in ACU - you would mostly likely lose the data. I have not experimented with reconfiguring a drive with the SAME configuration to see what would happen.

[Uwe Zessin]

> I've a drive that I'd like to move to another server but I need the data on it.

If you power down the server, plug in the disk drive which is a self-contained array, shouldn't the Smart Array controller automatically 'import' this array+ logical disk after power-up so that there is no need to configure it explicitly?

[kris rombauts]

Dan,

your description of the scenario/question isn't 100% clear to me either.

Uwe is absolutely right and if you folluw the steps (insert disk from old server in new server while the new server is powered off) then any array with any kind of raid level (0,1,5,..) will be imported into the new controller and no data will be affected.

Maybe the disk manager (i.e. Windows) will have to put a drive letter on that disk but that's about all you need to do before you are able to access the data, this under the condition that the OS version used here is compatible.

HTH

Kris

[Dan Hawker]

Hi All,

Thanks for the responses, I'll try and answer your queries...

I have inherited (new job) a DL380 G3 that runs Linux. It is presently setup as a single disk, configured as Array A and populates Slot-0. For clarity call this ServerA.

I also have an identical DL 380 G3 that has 4 drives configured as a RAID5. This is configured as Array A and populates Slots 0-3. (ServerB)

ServerB is also Linux and uses Xen (an open source virtualisation tech). What I planned to do is migrate the (poorly utilised) serverA to serverB but running as a VM. Predominantly for ease and speed, I hoped I'd be able to power down serverA, pop the drive and insert into serverB (in slot 4 or 5), light it up using the ACU and then get Linux to access the drive as normal. I could then use Xen to start up serverA as a VM, using the drive and data from serverA.

However, when I tried this, the ACU recognised the newly inserted drive, but didn't do anything with it. It just labelled it as an *Unallocated drive*.

I didn't like the sound of creating an array, as I presumed (rightly it seems from previous answers) that it'd hose my data. However I couldn't find a sensible way to start it up. I presumed it would *just work*; the array would see the drive and do its magic to allow Linux to access the drive, but it seems this is not the case.

Hope that clarifies my problem/scenario and what I'd like to achieve. It seems a pretty simple problem, but so far I haven't worked out if it is possible.

Thanks again for your responses.

Dan

[Dan Hawker]

Hi All,

Re-reading things again. Am I correct in assuming that you have to power-off the target server (serverB in my case) and power it back on for the SA to import any new devices???

I thought this was a hot-swap server??? This kind of scenario (along with RAID rebuilds) are exactly why hot-swap drives are useful.

The target server is a heavily used production server (with a couple of VMs running on it), and as such powering off/on again is not something I can do at the drop of a hat.

Thanks

Dan

[Uwe Zessin]

> I thought this was a hot-swap server???

Ahem. This is for failed components. What you intend is a configuration change. The SmartArray controllers pick them up during power-on in order to detect any drive roaming.

You are expecting a little too much.

[Dan Hawker]

Hi Uwe,

> You are expecting a little too much.

I guess I am :(

Ah well, so if I understand correctly, yes it should work (ie the SA will read the disk fine and import the array), however to do so I'll have to reboot the box.

Guess I'll have to arrange a reboot in the next few days.

Thanks for your replies everyone :)

Dan