摘要:
A method, system, computer program product, and computer program storage device for receiving and processing I/O requests from a host device and providing data consistency in both a primary site and a secondary site, while migrating a SRC (Synchronous Peer to Peer Remote Copy) from a backend storage subsystem to a storage virtualization appliance. While transferring SRC from the backend storage subsystem to the storage virtualization appliance, all new I/O requests are saved in both a primary cache memory and a secondary cache memory, allowing a time window during which the SRC at the backend storage subsystem can be stopped and the secondary storage device is made as a readable and writable medium. The primary cache memory and secondary cache memory operates separately on each I/O request in write-through, read-write or no-flush mode.
摘要:
A method, system, computer program product, and computer program storage device for receiving and processing I/O requests from a host device and providing data consistency in both a primary site and a secondary site, while migrating a SRC (Synchronous Peer to Peer Remote Copy) from a backend storage subsystem to a storage virtualization appliance. While transferring SRC from the backend storage subsystem to the storage virtualization appliance, all new I/O requests are saved in both a primary cache memory and a secondary cache memory, allowing a time window during which the SRC at the backend storage subsystem can be stopped and the secondary storage device is made as a readable and writable medium. The primary cache memory and secondary cache memory operates separately on each I/O request in write-through, read-write or no-flush mode.
摘要:
A method, in an oversampling clock and data recovery system, for detecting that sampling is stuck taking place at a data edge, by detecting a data edge in an early or a late region relative to a good region and incrementing a stuck early or stuck late counter; and if one counter reaching a maximum, setting a condition indicating that sampling is stuck taking place at a data edge. If a data edge is detected in the good region, or in each of an early and a late region in a single data period, the stuck counters are reset to zero. The detection of which stuck counter has reached a maximum can cause the moving of a sampling clock forward or backward, ending when a data edge occurs in a good region, or in each of an early region and a late region in a single data period.