Instructions
Thin-provisioned storage resources
When you create a thin-provisioned storage resource, you specify a target size for the resource. The size represents the maximum capacity to which the storage resource can grow without being increased by an administrator. Unisphere reserves only a portion of the requested size, called the initial allocation. The requested size of the storage resource represents a subscribed quantity. Thin-provisioned LUNs do not have an initial allocation. For thin-provisioned file systems, the initial allocation is 3 GB. Additional storage is allocated on-demand.
When a host or application uses approximately 75% of its initial allocation, an additional incremental quantity of storage is automatically allocated to the storage resource. The incremental allocation process continues until the quantity of storage allocated for the storage resource reaches the limit determined by its target size.
Pool subscription levels
All pools support thin-provisioned storage resources. For thin-provisioned storage resources, only incremental portions of the size are allocated based on usage. Because thin-provisioned storage resources can subscribe to more storage than is actually available to them, pools can be over-provisioned to support more storage capacity than they actually possess. Unisphere automatically generates notification messages when total pool usage reaches 85% of the pool's physical capacity. (You can customize this threshold).
Change pool properties
Procedure
1. Under Storage, select Pools.
2. Select the relevant pool, and then select the Edit icon.
3. On the General tab, optionally change the pool name and description.
4. On the Disks tab, review the characteristics of the disks in the pool.
5. On the Usage tab, select Capacity to view the amount of free space in the pool, subscribed pool capacity, and pool used capacity history. You can also change the alert threshold.
The subscribed space used is the percentage of the pool's total space that has been requested by its associated storage resources. When this value is over 100%, the pool is oversubscribed.
The alert threshold is the percentage of storage allocation at which Unisphere generates notifications about the amount of space remaining in the pool. You can set this value between 50% and 84%.
Select Storage Resources to view the total space used by storage resources and snapshots. You can also delete pool snapshots.
6. On the FAST VP tab (which appears if FAST VP is licensed), view data relocation and tier information for the pool. You can also exclude the pool from data relocations, manually start or stop data relocations for the pool, and manually move data to different tiers. Click Manage FAST VP settings to manage system-wide FAST VP settings.
7. On the Snapshot Settings tab, review and optionally change the properties for snapshot automatic deletion.
Additional Information
A thin-provisioned file-based storage resource may appear full when data copied or written to the storage resource is greater than the space available at that time. When this occurs, the system begins to automatically extend the storage space and accommodate the write operation. Try the write operation again. As long as there is enough extension space available, this operation will complete successfully.