Abstract: Described are techniques for cache management that may include determining whether to flush dirty cached data included in a flash disk cache. Caching layer may include the flash disk cache as a secondary cache and another cache as a primary cache. Responsive to determining to flush dirty cache data from the flash disk cache, first processing may be performed that includes flushing dirty cached pages from the flash disk cache to one or more physical storage devices. The dirty cached pages may include data from a plurality of logical addresses of a first device. The logical address may be sorted and included in a sorted list. Flushing may include writing the plurality of dirty cached pages in an ordering in accordance with the sorted list.

Abstract: A technique for managing file systems that support block sharing places a source/copy attribute in each block pointer. The source/copy attribute identifies the respective block pointer as either a source-block pointer or a copy-block pointer. A reference count on each data block maintains a count of the number of source-block pointers pointing to the data block but excludes the number of copy-block pointers pointing to the data block. Block pointers are arranged in block pointer sets (BPSs), and sharing relationships are formed among BPSs and copies of BPSs. The sharing relationships generally keep most block sharing information at the BPS level, with reference counts on data blocks tracking only the number of source-block pointers, which is typically small, often being equal to one.