Detecting Oversubscription Situations (Thin Provisioning)

We call an oversubscription situation when:

1.The storage pool is configured for thin provisioning (“thin storage pool”)

2.The storage pool is oversubscribed, i.e. the total disk space visible to the hosts (subscribers) is greater than its actual capacity (this situation is normal for a thin pool since it is its very purpose)

3.The storage pool actual consumed capacity is nearing 75%

Such situation is highly critical because the inability to allocate additional space to a LUN when requested by the subscriber host will lead to catastrophic data loss and corruption.

When the conditions described above are met, the solution sets the Oversubscription Situation parameter to 1, automatically raising a warning. By default, the threshold for the Consumed Capacity Percentage parameter is set at 75%. This threshold can be configured in the input properties of the solution.

Configuring Oversubscription Threshold

1.Click the EMC Disk Arrays icon and then the Configure tab.

2.Edit the Oversubscription Situation Threshold (%) property to the appropriate value. When the Oversubscription Situation parameter triggers a warning, it is highly recommended that the SAN administrators add capacity to the storage pool as soon as possible.