Abstract: Detection and reduction of unaligned input/output (“I/O”) requests is implemented by a storage server determining an alignment value for data stored by the server within a storage system on behalf of a first client, writing the alignment value to a portion of the volume that stores the data for the first client, but not to a portion of the volume that stores data for a second client, and changing a location of data within the portion of the volume that stores the data for the first client, but not a location of data in the portion of the volume that stores data for the second client, to an alignment corresponding to the alignment value. The alignment value is applied to I/O requests directed to the portion of the volume that stores the data blocks for the first client after the location of the data blocks has been changed.

Abstract: Just-in-time segment cleaning obtains the location of blocks of a storage system predicted to be targeted by a future write operation and cleans the blocks targeted for the future write operation prior to the occurrence of the future write operation. In one aspect, just-in-time segment cleaning is performed in proportion to previous user-initiated write operations. In another aspect, just-in-time segment cleaning applies a cost analysis determination to minimize the work of cleaning.

Abstract: Methods and apparatuses provide a multi-level buffer cache having queues corresponding to different priority levels of queuing within the buffer cache. One or more data blocks are buffered in the buffer cache. In one embodiment, an initial level of queue is identified for a data block to be buffered in the buffer cache. The initial level of queue can be modified higher or lower depending on a value of a cache property associated with the data block. In one embodiment, the data block is monitored for data access in a queue, and the data block is aged and moved to higher level(s) of queuing based on rules for the data block. The rules can apply to the queue in which the data block is buffered, to a data type of the data block, or to a logical partition to which the data block belongs.