Method and apparatus for cache synchronization in a clustered environment

A method of reading data from cache in a clustered environment comprising:

• receiving a request to read data in a first node of a storage duster from a host;
• allocating a track in cache of the first node for the requested data;
• obtaining the data into the cache prior to requesting or obtaining a lock state change from a second node responsible for the data;
• providing the host with access to the data.

An apparatus for writing cache in a clustered environment comprising:

• (a) a cache;
• (b) a first storage node and a second storage node organized in a storage cluster, each storage node having an interface for connecting to a host and a storage disk, wherein each storage node maintains cache, and wherein the first storage node is configured to:
• (i) receive a request to write data front a host;
• (ii) obtain allocated memory space in the cache of the first storage node;
• (iii) receive the data into the allocated memory space from the host prior to the first storage node receiving permission for a write operation from the host or the second storage node that is responsible for a lock state of the memory space in cache, wherein the secondary node later sorts out proper order for cache coherency;
• (iv) notify the second storage nodes of the request to write data;
• and
• (v) transfer the data from the first storage node to the second storage node.

An apparatus for reading cache in a clustered environment comprising:

• (a) a cache;
• (b) a first storage node and a second storage node organized in a storage cluster, each storage node having an interface for connecting to a host and a storage disk, wherein each storage node maintains cache, and wherein at least one of the storage nodes is configured to:
• (i) receive a request to read data from a host;
• (ii) obtain allocated memory space in the cache;
• (iii) obtain the data into the cache prior to requesting or obtaining a lock state change from a node responsible Lot the data;
• and
• (iv) provide the host with access to the data.

An article of manufacture, embodying logic to perform a method of writing cache in a clustered environment, the method comprising:

• receiving a request to write data in a first node of a storage cluster from a host;
• obtaining allocated memory space in cache of the first node for said data;
• receiving the data into the allocated memory space from the host prior to the first node receiving permission for a write operation from the host or a second node responsible for a lock state of the memory space in cache, wherein the secondary node later sorts out proper order for cache coherency;
• notifying the second node in the storage cluster of the request to write data;
• and
• transferring the data from the first node to the second node.

An article of manufacture, embodying logic to perform a method of reading cache in a clustered environment, the method comprising:

• receiving a request to read data in a first node of a storage cluster from a host;
• allocating a track in cache of the first node for the requested data;
• obtaining the data into the cache prior to requesting or obtaining a lock state change from an owner of the data;
• and
• providing the host with access to the data.