Re: 283GB Drives in a set of 139GB Disks..

On Sat, 2014-04-26 at 23:45 -0400, DrFranken wrote:

Here is the pic from Service Tools:

Set ASP Unit Type Model Name Status
1 57B5 001 DC14 RAID 5
2 2 19B0 099 DMP064 Active
2 3 19B0 099 DMP066 Active
2 5 19B0 099 DMP040 Active
2 4 19B0 099 DMP042 Active
* * 19B1 090 DMP080 Active
* * 19B1 090 DMP085 Active

Note that the 19B0s are 139G and the 19B1s are 283s....

That's fairly standard for raid, the device with the least amount of
storage is the maximum unit size of all members of the raid array.

Having said that, it would be impossible to add a device that was
smaller than the smallest device currently a member of the raid group,
at least as far as windows/x86/linux-mdadm is concerned, unless the os
could go through a total re-sequencing of all members to reduce the size
of the larger members to the new "smallest" drive. (linux-mdadm requires
manual intervention to re-size the current partitions, on every disk,
down in size, then add the new member, and then a re-sync is kicked off
to re-map the checksum/data across all the members) Adding a larger disk
would produce no report/error/warning but would obviously not use any
space that was larger than the smallest member size.

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 4/26/2014 11:39 PM, DrFranken wrote:

In a first for me as I did not think it possible. I added two disks to a
partition that had both 139s and 283s. The 139s are in ASP(2) and there
are only 6 of those. The 283s are ASP(1) and the two RAID sets there are
at the limit of 18 drives each.

After initializing the two drives (they are used) I selected 'Include in
RAID protection' in SST. I didn't read the confirmation screen closely
enough and let them add to RAID.

When I went to add them to the ASP I DID read that confirmation screen
to confirm that I would be adding 566 GB but NO it was only 278! Upon
further review of the RAID sets I saw that the 283GB drives were now
part of a 139GB drive raid set and only that much of their capacity was
in use.

Didn't know this was even possible....

5913 RAID cards on POWER7 with TR6 of IBM i 7.1...