You cannot perform the following operations on a pool while the pool volume capacity is in the process of shrinking. Wait until shrinking completes or stop the shrinking process.About decreasing pool capacity
You can decrease pool capacity by deleting pool-VOLs.
When a pool-VOL is removed from a pool, all the used pages in the pool-VOL are moved to other pool-VOLs.
When you delete a pool or decrease the pool capacity, the released pool-VOLs (LDEVs) will be blocked. If they are blocked, format them before using them. If the blocked pool-VOL is an external volume, use Normal Format when formatting the volume.
You can decrease pool capacity for up to eight tasks at the same time. Do not execute a Command Control Interface command to also decrease the capacity of the pool whose capacity is already in the process of being decreased.
You cannot decrease pool capacity while doing any of the following to a pool.
Creating the pool.
Deleting the pool.
Increasing the pool.
Decreasing the pool.
Recovering the pool.
Stopping decreasing the pool.
Changing the threshold.
Reclaiming zero pages.
Creating DP-VOLs.
Increasing DP-VOL capacity.
While the pool capacity is being decreased, if maintenance of cache memory is performed, if the cache memory fails, or if the I/O load to the DP-VOL related to the pool is high, decreasing the pool capacity process might fail. In this case, check the Tasks window to determine whether processing has abnormally ended.
If the processing has ended abnormally, restore the cache memory, then try decreasing the pool capacity again.
You cannot perform the following operations on a pool while the pool volume capacity is in the process of shrinking. Wait until shrinking completes or stop the shrinking process.
Expand Pool
Shrink Pools
Edit Pools
Restore Pools
If you delete the pool-VOL with the pool's system area, the used capacity and the management area will move to other pool volumes. If you delete the pool-VOL with system area, a different system area pool-VOL will be assigned automatically according to the priority shown in the following table. A pool must include one or more pool-VOLs.
|
Priority |
Data drive type |
|---|---|
|
1 |
SAS7.2K |
|
2 |
SAS10K |
|
3 |
SAS15K |
|
4 |
SSD |
|
5 |
External volume |
If multiple pool-VOLs of the same data drive type exist, the priority of each is determined by internal index of the storage system.
If pool capacity is decreased soon after creating a pool or adding a pool-VOL, processing may take a while to complete.
Notes on using Dynamic Provisioning
You cannot delete a pool-VOL under these conditions.
If the pool-VOL is deleted, the used capacity of the pool-VOL exceeds the pool threshold.
If the pool-VOL is deleted, the subscription rate of the total V-VOL capacity including the control information exceeds the subscription limit. For details about the formula used to calculate the required pages for one DP-VOL including the control information, see Pool subscription limit.
If the pool-VOL with system area is deleted, more than 4.2 GB of free space is necessary in the pool.
Notes on using Dynamic Tiering
You cannot delete a pool-VOL under these conditions.
If the pool-VOL is deleted, the used capacity of the pool-VOL exceeds the pool threshold.
If the pool-VOL is deleted, the subscription rate of the total V-VOL capacity including the control information exceeds the subscription limit. For details about the formula used to calculate the required pages for one DP-VOL including the control information, see Pool subscription limit.
If the pool-VOL with system area is deleted, more than 4.2 GB of free space is necessary in the pool.
When the pool-VOL is deleted, the pages contained in the deleted pool-VOL transfer to another pool-VOL in the same tier. If the used capacity in the tier exceeds Rate of Free Space Newly Allocated to, the overflowing pages transfer to another tier.
When pool-VOLs in the tier are empty, the appropriate tier is deleted.
Deleting the pool-VOL stops tier relocation. The process resumes after the pool-VOL is deleted.
Notes on using Thin Image
You cannot delete a pool-VOL under these conditions.
If the pool-VOL is deleted, the used capacity of the pool-VOL exceeds the pool threshold.
If the pool-VOL with system area is deleted, more than 4.2 GB of free space is necessary in the pool.