How do I add second array to RAID1 array of basic disks?

[Shinken]

I have an IBM x225 Server with a single RAID1 array of two 36GB SCSI hot-swappable drives. The RAID1 array was set up with basic disks. Controller is Ultra320.

We recently took delivery of two additional 36GB IBM Ultra320 drives, which I set up as a second RAID1 array, and as dynamic disks.

I want to add the second array to the first array. My understanding is that I must break the first array's mirror, upgrade the mirrored partition of the first array from basic to dynamic disk, recreate the mirror, and then I can span the two dynamic arrays.

I have not worked with the ServeRAID software until recently, nor have I every spanned 2 arrays. The ServeRAID manager has no "break mirror" option. I've reviewed the IBM documentation, website, etc., but the only references I can find, refer to deleting an array and all of the contents of the drives. I want to non-destructively upgrade the existing array to dynamic disks so that I can add the second array to it.

Why not just leave the second RAID1 array as a different drive letter for users? Mostly, this is a small domain (11 users) and it will be simpler for users users, who will just see more space available, rather than remapping, etc.

Even with a backup image ready, I would prefer to complete this process without minimum muss & fuss, which equates to downtime.

FIRST QUESTION: Is the generalized process in paragraph 3 (above) the correct method for merging the two arrays?

SECOND QUESTION: Can someone provide me with step-by-step instructions for accomplishing my goal? A link to this info would be fine.

Thanks,

S

 

[ibmtech65]

First question would be are you using the onboard controller? If you are then it is not going to support spanning and I believe it only does 1 raid1 array.

 

[Shinken]

Not using the onboard controller.

According to the ServeRAID Manager, the controller is an IBM ServerRAID 5i (BIOS ver 5.11.05).

There are 6 hot-swap bays in the front of the server, 2 of which were originally filled with the RAID1 array (basic disk). Last week, I added 2 more IBM hot-swappable drives and created a second RAID1 array, and configured these drives as dynamic.

According to the documentation for the 5i controller, it should support RAID5 as well as spanning, unless I have misread the docs.

 

[ibmtech65]

Only way to span them would be to delete your arrays and create the 2 arrays at the same time and check spanning.

 

[Shinken]

Yikes! Are you sure?

I don't believe that IBM would not provide a means to add additional drives to a RAID1 array. The usual means is to just create a second array and add it to the first array.

Perhaps I'm asking the wrong question. Maybe spanning 2 arrays isn't the way to do it. Is there a way to add 2 additional and identical drives to an existing RAID1 array in order to expand the storage capacity of the array?

 

[ibmtech65]

Yes I am sure. Tested it myself in raidmanager. Since you already had an array created when you go to create a new array with the new drives it will not list the other array so you can not do spanning.

Your options if you did not want to loose any data would be to do a logical drive migration. That will change your array from Raid1 to raid1E and you will only get half of the space avail on the disk or disks. Or you could get a good back up and create a raid 5 with you 4 disks, provided they are all the same size, and get even more space then the raid1E.