I have a storage array with 2 DE6600 disk shelfs and 2 E5600 series controllers and SANTricity Manager 11.20.
I have a disk pool with 60 drives (550 GB each drive) and its status shown in Recovery Guru is Failed. There is only one drive
with the status "Impending failure (reported by drive)" and mode "Drive copy pending" and all the other 59 drives in the pool are optimal. I have deleted a volume so that now the disk pool is occupied 75%. 25% of the disk pool capacity is free capacity (approx. 6TB; the totap capacity of the disk pool is 25TB). SANTricity Manager reports that Preservatio capacity (drives dedicated to preservation capacity) is 0. The problem is that I can not increase this number even if 25% percent of the total capacity of the disk pool is free capacity. And I can not change the status of the disk pool to omptimal.
At this point, you may want to go ahead and fail the drive manually. The rest of the pool will be able to continue reconstruction without this drive. Once reconstruction of the pool has completed, you can join the new drive into the pool (I'm assuming you have a replacement drive).
This TR should give you more understanding of how DDP works: TR-4652 SANtricity Dynamic Disk Pools (netapp.com).
Hi Mitch. Thanks for your message and the technical report (it was instructive). My thinking is in the same line as yours: if I fail 1 drive, because there is more than 20% free capacity in the disk pool, the disk pool should be able to reconstruct the missing data and become optimal. Indeed, I actually have two disk pools, each having 60 drives, each having 1 failed drive. The problem is that one pool (named GPFS in the disk-pool.png picture attached to this message) was able to keep an "Optimal" state with one failed drive even if the free capacity in the pool is very small. But the other pool, named CLOUD, with 1 failed drive has a "Failed" state even if the free capacity in the pool is more than 20% the size of the pool. In the attached pictures (disk-drives-.png) you can see all the drives and the ones belonging to the CLOUD disk pool are marked with green.
I'm sending you in a following message some pictures with the errors from the Recovery Guru related to the CLOUD pool, if you somehow have a little time to look over them.
Hi Mitch, I'm posting here some pictures with the errors from the Recovery Guru related to the CLOUD pool (the other errors not shown in the pictures are related to the GPFS pool and to a failed battery in one of the controllers). I don't know why Recovery Guru says "Current recovery drive count: 0" as the preservation capacity drive count is 3 in the "Settings" menu of the CLOUD disk pool.