Exchange disks on AutoRAID 12H

[Verónica Muñoz Segovia]

Is it possible to exchage an 9 Gb disk assigned to a volume group by a new one 18 Gb diks, or I need first to backup in order to exchange the disk and then recreate the LUN and VG and restore the information.

Thanks

[Andreas Voss · Accepted solution]

Hi,

if you are using LUN's (no dedicated disk) from your AutoRAID you don't have to care which disk types are used. Simply replace 9GB with 18GB but do it disk by disk and give the AutoRAID time to do balancing.
One thing to whatch out:
The fan modules for 18GB disk must be the newer ones (they have raised blue labels on it, the old ones have flat labels).

Regards

[Verónica Muñoz Segovia]

Thanks, very much!!!!

Veronica

[Don Bentz]

Veronica, another thing you need to be aware of is if you already have 8 LUNs created, I believe you will not be able to use the additional space for logical volumes (without considerable effort). I have a similar situation I am trying to remedy, see my inquiry about this dated 10/23/2000 in this forum.

[Verónica Muñoz Segovia]

I know there are a luns limit creation, but know I am more confuse, because I had a contradiction answer. A friend told me that is not possible to replace one 9 Gb disk by a newly 18 Gb disk because the disk is assigned to a vg. This was the answer of my friend:

"If the disk is configured in a volume group, you cannot replace one 9 Gb disk by another one with different size, because the autoRAID will have troubles to can sincornized the info, because is a dispositive with diferent characteristics. If you want to replace this disk because you have not more available slots, you must to do first a fullbackup of the array, delete the actual volume groups, remove the disk,
reinicialize the array and create the new volume groups. The new capacity of the array will be show it whe you reanicialize the array.

[Don Bentz]

I suspect your friend is refering to LUNs when he says "slots", in which case, I refer to my original statement. If you have 8 devices files (physical volumes) on that array, he is correct. You will be doing exactly what I am doing, backing up the data, removing the volume groups/physical volumes, then rebuilding the volume group(s) associated with the array from the beginning. Last of all you will restore your data to the new, larger, "volumes". If anybody else knows otherwise, please feel free to save us from this dreadful task.

[Verónica Muñoz Segovia]

No, my friend in effect is reffering to slots, because I have full the array, all the twelve slots are ocupated by ten 9 Gb disks, and two 18 Gb disks, and all the space is allocated by vg10.

And just as a comment, like you I was pretending to replaced my 9 Gb disks by 36 Gb disks, but my supplier told me that they have reported cases where this configuration creates performance troubles, because these are more slow, he didn't recomend me to exchange them to 36 Gb.

[Don Bentz]

Not sure what I was thinking, of course he meant physical disk slots. Anyway, the 36-gig drives I have are 10,000RPM disks and the 18.2-gig disks I am replacing are 7,200 RPM. Unfortunately, I don't have a great deal of choice, I need more disk space and I have no I/O slots left on this K260 server. I already have 2 AutoRAIDs daisy-chained, not adviseable, I know. But... Thanks for the information.

[Don Bentz]

Not sure what I was thinking, of course he meant physical disk slots. Anyway, the 36-gig drives I have are 10,000RPM disks and the 18.2-gig disks I am replacing are 7,200 RPM. Unfortunately, I don't have a great deal of choice, I need more disk space and I have no I/O slots left on this K260 server. I already have 2 AutoRAIDs daisy-chained, not adviseable, I know. But... Thanks for the information.