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Possible to change the logical number

Steve_P
Advisor

Possible to change the logical number


Hi All,

I am wondering if there is a way to change the logical number from higher to lower number using some kind of utility.

I found out it always boots off the logical drive with a lower number, for example, if there is two logical drives with logical drive #1 and logical drive #2, it will boot from logical drive #1. Or, if you have logical drive #2 and #3, it will boot off logical drive #2.

I was trying to replace the logical drive from raid 5 to raid 1 and use a third party software to copy the partitions, copying the partitons was not an issue but booting up from the new raidset was. I was able to create another raidset and managed to keep the logical number for the boot partition the least and it finally boot from the logical drive I wanted.

Maybe, there is an other simple way to do, I would appreciate to hear it.


Thanks,

Steve


5 REPLIES
Steven Clementi
Honored Contributor

Re: Possible to change the logical number

Steve:

Can you give us some more information as to what hardware you have?

Server type... Storage.. Internal? External?

Running OS?

Generally, you can not change the Logical Disk number unless you are using a more enterprise level storage array. It does not sound like you are in this case.

The lower numbered logica; drive is always "seen" first by the OS. THe only way you can boot off of a higher numbered logical drive is to change your boot loader config file.

If you are using a Smartarray Controller, you may be able to "migrate" to a different raid level if you have the available space.


Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
Steve_P
Advisor

Re: Possible to change the logical number


Sure do.

I am testing it on DL385-G1 using SA-6i controller running with Windows 2003 STD with SP1.


Thanks,

Steve



Steve_P
Advisor

Re: Possible to change the logical number


I beleive it is the way it works as designed.
The only I can change that is to create new array along with the existing array, which makes the new array logical number lower than the existing one. Then using third party software to copy the partitions.

B. Faulk
Occasional Visitor

Re: Possible to change the logical number

Actually, what I just did was"

1. power down and pull the drives on the array I want to be #1 but is currentl #2 (or #3)

2. Delete the "failed" array and add 3 new arrays temporarily. You can swap spare drives in the original cage if you make sure you number your pulled disks for reinsertation later.

3. Save the array and reboot

4. delete array #1, save, and reboot/power down.

5. put the original drives back in. Since array #2 (or #3) is still used it doesn't use the array stored with the drive and #1 is assigned.

Luca
Advisor

Re: Possible to change the logical number

I just wanted to add the following because I believe it is a shame there is no way to reassign the logical drive number via the ACU or CLI.

Briefly put, we had to merge some partitions and copy data to another offsite machine (always an ML350G3)so we brought the RAID array disks to the new location machine copied the data and brought it back. The array now had become Logical ID 2. However, the original machine had another array which was already logical ID 2 (a 3 disk RAID 5 array) which stored other data. When we popped the original boot mirror back in (we had already deleted the first array at the other machine removing the other boot drives first to clear the array data of the missing drives) instead of becoming Logical ID 1, it remained 2 and the non boot array BECAME LOIGAL ID 1. Absurd.

After testing with other machines, we discovered that in a concurrent situation (same logical ID number) the Smart Array (in this case 641) automatically reduces the logical ID of the SECOND volume in a row (the one with higher ID number) instead of lowering the first!

However, thanks to this we were able to force the first volume to become logical ID 1 again, by simply moving the array at the end of the cage, and popping in ANY logical ID 2 in the first IDs (after having cleared the relevant missing disk array data from the volumes first). This way, the last 2 disks which were our boot mirror with logical ID 2 became ID 1 thanks to this absurd reasoning. We then cleared the missing disk array data again and put the mirror back into itàs original position where it udated and booted regularly.


I ask myself, is it so unprobable to have the necessity to move disks/arrays from one machine to another and then move them back? I think this is a normal condition. Even the basic Smart Array should have an embedded possibility (via ACU) to edit the logical volume number. The older NetRaids had many more options in the BIOS which gave you much more leverage without having to boot from a USB drive or use a working machine to edit your setup.

I propose to implement an option to modify the logical volume number directly via the ACU as this is the only direct and quick way to save time and fix your arrays without having to go through all this disk swap hassle where any error can cost you a lot.

I read somewhere that the only way to get back to logical ID 1 was to "backup your data and recreate your array" - you must be kidding me.

I am glad to offer this information to any of you out there that have encountered this problem and I sincerely hope that some developer at hp understands and implements this option and finally puts an end to the swap hassle (and fix the Array ID weirdness).

Thanks!