| 摘要 |
A method of managing a storage system which includes a local and remote systems is provided. Link services between the two subsystems are provided though the use of a task queue. The task queue resides in a global memory of the local storage system and receives requests from the various host controllers, device, and remote controllers connected to the local storage. The remote controllers of the local storage service the requests placed in the task queue to enable data transfer between the local and remote storage systems. The task queue may be a doubly linked list of records including forward and backward pointers in addition to the request data. A two level locking scheme is employed to prevent the addition of incompatible requests to the queue and to enable maximum parallelism in servicing requests in the queue. The first level of locking applies to the entire queue and is used when records are added to and deleted from the queue. The second level of locking applies to the individual queue records. Each queue record is locked when being serviced by an associated controller. Locked records and records corresponding to device requests having another locked record are ignored by the servicing controllers.
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