International Business Machines Corporation

Richard Alan Bordoli

Miles Mulholland

Roderick Guy Charles Moore

William John Passingham

Timothy A Moran

Christopher W Bulmer

Andrew D Martin

Garbage collection is performed for a virtualized storage system whose virtual address space is addressed in extents. Valid data in source extents is copied via a cache into destination extents. Once all valid data in a source extent is copied into one or more destination extents, the source extent may be reused. A source extent is released for reuse only after the one or more destination extents that received the valid data copied from the source extent are determined to be full, and the valid data copied from the source extent to the destination extent via the cache is flushed out of the cache.

Protecting against data loss during garbage collection

A storage area network comprises: one or more replicating source and target storage volumes accessible by one or more hosts; a volume replication status checker for determining an active replication relationship between a source storage volume and a target storage volume; and a volume visibility engine for setting the target storage volume to be hidden from a host if the target storage volume is visible to the host and has a determined active relationship. The volume replication status checker is further for determining an inactive replication relationship between a source storage volume and a target storage volume; and the volume visibility engine is further for setting the target storage volume to be visible to a host if the target storage volume is hidden from the host and has a determined inactive replication relationship.

Managing disaster recovery replication for storage volumes

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Hampshire, United Kingdom

Richard Alan Bordoli