Monitoring pool capacity
The storage system monitors the pool's free capacity in accordance with threshold values defined when you create pools. If the pool capacity reaches the threshold values, warnings are issued as SIMs and as SNMP traps to the open-systems host.
You can provision a larger virtual capacity beyond the pool capacity by using DP-VOLs of Dynamic Provisioning or Dynamic Tiering. However, when the pool's free capacity is depleted, you can lose access to DP-VOLs that require more pool capacity. For example, if the pool usage rate is 100% due to increased write operations, then I/O is not accepted and I/O will be stopped for a DP-VOL that failed to receive needed pool capacity. Therefore, you should carefully monitor the pool usage or pool free capacity, as well as the level of provisioned virtual capacity.
Protecting data during pool shortages
To protect data from reading and writing to the DP-VOL when the pool is full, you can apply access attributes to a volume. To do this, you need to enable the use of the Hitachi Data Retention Utility, by insuring the license is installed and using system option mode 729. This protection method applies a Protect attribute to the DP-VOL to protect volumes against write operations when the pool is full. See Assigning an access attribute to a volume for more details.
The Protect attribute is applied to the DP-VOL and is used in conjunction with other Hitachi software products. When the Protect attribute is applied to the DP-VOL, Permitted appears in the S-VOL field and appears in the field of the Hitachi Data Retention Utility window. However, when the Protect attribute is added to the DP-VOL with the S-VOL unacceptable attribute available in the Hitachi Data Retention Utility, Not Permitted appears in the S-VOL field in the Data Retention window.