Copy threshold option and host server I/O performance for Thin Image

You can enable the copy threshold option to help minimize the decline of host server I/O performance by lowering the workload on the storage system.

I/O performance of the host server might be lowered as the workload on the storage system increases. If you perform Thin Image restore operations when the workload on the storage system is high, I/O performance of the host server is more likely to be lowered because replication processes for the primary volumes are triggered. The copy threshold option can be used to temporarily stop the replication processes triggered by the restore operations when the workload on the storage system is high. The copy threshold option can contribute to minimizing the decline in I/O performance of the host server.

The copy threshold option is applicable only when the workload on the storage system is excessively heavy. If the copy threshold option is applied, all the replication processes triggered by restore operations are stopped.

Replication processes stopped by the copy threshold option will be restarted as the workload on the storage system is lowered. Enabling the copy threshold option stops replication processes for Thin Image and the following products when the storage system is overloaded.

  • ShadowImage
  • ShadowImage for Mainframe
  • Compatible FlashCopy® V2
  • Volume Migration

For more information about enabling the copy threshold option, call the Hitachi Solution Support Center.

For more information about Compatible FlashCopy® V2, see the Compatible FlashCopy® User Guide (Compatible FlashCopy® V2, Compatible FlashCopy® SE).

Related Concepts
  • Thin Image pair restoration

    You can use Thin Image to overwrite snapshot data in pools to P-VOLs so that the P-VOL content is returned to the condition it was when you stored snapshot data.

Parent Topic
  • Overview of Thin Image

    With Thin Image (HTI), you can perform cost-effective replication by storing the differential data between primary volumes (P-VOLs) and secondary volumes (S-VOLs) of virtual volumes (V-VOLs). You can also copy data of an entire volume, instead of copying just the differential data, to a volume. By copying the entire volume, you can expect a higher performance than by just storing the differential data.