Emc IP Holding Company LLC

Guoyu Hu

Shuo Lv

Qiaosheng Zhou

Congyue Gu

Chen Gong

Huan Chen

Jian Qiang Liu

Chao Han

Techniques delete snapshots. The techniques involve: in response to a data block to which a plurality of snapshots of a file to be deleted point being shared, determining whether a physical address of the data block to which the plurality of snapshots to be deleted point is the same as a target physical address of a data block to which a target snapshot of the file points. The techniques further involve: in response to the physical address of the data block to which the plurality of snapshots to be deleted point being the same as the target physical address, setting flag bits associated with the plurality of snapshots to be deleted to a first state. The techniques further involve: in response to detecting the first state, updating a target weight with a sum of weights of the plurality of snapshots to be deleted (e.g., respective quotas).

Method, device and computer program product for deleting snapshots

Embodiments are directed to techniques for allowing a data storage system to be able to flush data to underlying storage when the bandwidth is high without excessively impacting the maximum latency. This may be accomplished by utilizing asynchronous flushing and by throttling incoming writes by preventing too many asynchronous flushes from happening when the amount of available cache space is too small. In addition, an improved system employing Copy on First Write (CoFW) may initiate write throttling only once the amount of available write cache drops below a dynamically-calculated threshold that accounts for an amount of space actually needed to store CoFW buffers. In addition, only a portion of the write caching process is placed under the protection of a mutex or a spinlock, allowing a significant portion of the write caching for any given write operation to be performed without needing the mutex or spinlock, allowing some increased parallelization.

Throttling writes with asynchronous flushing

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Beijing, China

Guoyu Hu