Storage recovery from total cache loss using journal-based replication

摘要

In one aspect, a method includes receiving write I/Os for storage in a primary storage array, splitting the write I/Os to a replica site, storing the write I/Os for storage in the storage array in a cache, periodically de-staging the write I/Os in the cache to a volume and after a cache data loss, restoring lost write I/Os from the cache by using the write I/Os split to the replica site.

主权项

1. A method comprising:
receiving write I/Os for storage in a primary storage volume of a storage array; splitting the write I/Os to a replica site; storing the write I/Os for storage in a cache of the storage array; periodically de-staging the write I/Os in the cache to the primary storage volume; after a cache data loss, restoring lost write I/Os from the cache by using the write I/Os split to the replica site; replicating the primary storage volume to form a replica volume; and recording the split write I/Os in a journal comprising a DO stream of writes I/Os not applied to the replica volume, wherein restoring the lost write I/Os comprises:
applying the DO stream to the replica volume;generating a first delta marking stream of differences between the replica volume and the primary storage volume; andapplying data matching dirty locations in the first delta marking stream to the primary storage volume.