Abstract: Architectures and techniques are described that can provide file system level attack mitigation techniques for a data storage service system or other network service system. By operating at a file system level, the disclosed techniques can access information that is unavailable at the block volume level and which can be leveraged to accurately identify a source of a potential attack. By accurately identifying a source of the potential attack, additional options are available for mitigating the potential attack.

Abstract: A technique for managing storage space includes establishing an MSR (minimum space reservation) of a thin file system built upon a storage pool. In response to a set of storage requests to the file system to store new data, the method further includes obtaining an additional space guarantee from the storage pool. After deleting data from the file system such that the size of the file system falls below the MSR, the technique further includes performing a space reclaim operation, the space reclaim operation (i) compacting the file system to a size less than the MSR, (ii) canceling the additional space guarantee such that the storage pool no longer guarantees the additional space for the file system, and (iii) continuing to reserve the full MSR of the file system, even though the size of the file system is smaller than the MSR.

Abstract: Techniques for storage management involve: if it is determined that a source storage slice of a file system is to be recycled, identifying, from the source storage slice including a plurality of storage blocks, an orphan storage block that is inaccessible by a client of the file system; replicating data of the orphan storage block to a target storage block, the target storage block being located in a target storage slice within a predetermined isolation area of the file system; and generating second metadata of the target storage block based at least on first metadata of the orphan storage block, the second metadata including at least an identification of the orphan storage block. Therefore, the management performance can be improved, and the storage costs can be reduced.

Abstract: Techniques for managing disks involve: determining a current usage parameter associated with each of a plurality of disk sets, the current usage parameter indicating usage associated with a capability of each of the plurality of disk sets, and the capability comprising at least one of the following: a number of permitted accesses per time unit and a number of permitted writes per time unit; imbalance degree associated with the plurality of disk sets, the first imbalance degree indicating a difference in the current usage parameters of the plurality of disk sets; and causing data in at least one disk slice of a first disk set to be moved to a second disk set of the plurality of disk sets, so as to lower down the first imbalance degree. In this way, a better balance can be achieved among performances of respective disks after adjustment.

Abstract: Techniques for storage management involve: if it is determined that a source storage slice of a file system is to be recycled, identifying, from the source storage slice including a plurality of storage blocks, an orphan storage block that is inaccessible by a client of the file system; replicating data of the orphan storage block to a target storage block, the target storage block being located in a target storage slice within a predetermined isolation area of the file system; and generating second metadata of the target storage block based at least on first metadata of the orphan storage block, the second metadata including at least an identification of the orphan storage block. Therefore, the management performance can be improved, and the storage costs can be reduced.

Abstract: Techniques for managing disks involve: determining a current usage parameter associated with each of a plurality of disk sets, the current usage parameter indicating usage associated with a capability of each of the plurality of disk sets, and the capability comprising at least one of the following: a number of permitted accesses per time unit and a number of permitted writes per time unit; imbalance degree associated with the plurality of disk sets, the first imbalance degree indicating a difference in the current usage parameters of the plurality of disk sets; and causing data in at least one disk slice of a first disk set to be moved to a second disk set of the plurality of disk sets, so as to lower down the first imbalance degree. In this way, a better balance can be achieved among performances of respective disks after adjustment.

Abstract: A data storage system manages use of a pool of secondary storage by internal file systems hosting logical data storage objects accessed by clients. A choose-and-mark-slices operation scans the file system to identify a subset of the slices as evacuatable slices to be de-provisioned and returned to the pool, the subset having a size exceeding a per-iteration limit observed by a separate evacuate-slices operation. The subset is recorded in an in-memory structure. Each iteration of the evacuate-slices operation (1) examines the in-memory structure to select slices for evacuation, no more than the per-iteration limit being selected, (2) moves data from the selected slices to the remaining slices of the set, and (3) subsequently (i) updates metadata of the file system to reflect the moving of the data and (ii) de-provisions the selected slices from the file-system to return them to the pool for subsequent re-provisioning.

Abstract: A data storage system manages use of a pool of secondary storage by internal file systems hosting logical data storage objects accessed by clients. A choose-and-mark-slices operation scans the file system to identify a subset of the slices as evacuatable slices to be de-provisioned and returned to the pool, the subset having a size exceeding a per-iteration limit observed by a separate evacuate-slices operation. The subset is recorded in an in-memory structure. Each iteration of the evacuate-slices operation (1) examines the in-memory structure to select slices for evacuation, no more than the per-iteration limit being selected, (2) moves data from the selected slices to the remaining slices of the set, and (3) subsequently (i) updates metadata of the file system to reflect the moving of the data and (ii) de-provisions the selected slices from the file-system to return them to the pool for subsequent re-provisioning.

Abstract: A data storage system manages a pool of secondary storage by internal file systems hosting logical data storage objects accessed by clients, the pool organized into fixed-size, dynamically provisioned slices. A first choose-and-mark-slices operation scans a set of slices to identify a first subset as evacuatable, and records them as a recorded subset in an in-memory structure. Iterations of an evacuate-slices operation (1) select slices from among the recorded subset, observing a per-iteration limit, (2) move data from the selected slices to remaining slices of the set, and (3) subsequently (i) updates file system metadata to reflect the data movement and (ii) de-provisions the selected slices and returns them to the pool. Between iterations, a change in the composition of evacuatable slices is detected, and a second choose-and-mark-slices operation re-scans the slices and records a second subset as the recorded subset for a subsequent iteration of the evacuate-slices operation.

Abstract: A method, computer program product, and computing system for defining an initial root slice for a storage system. A first data slice is defined for the storage system. The location of the first data slice of the storage system is identified within the initial root slice. A request for a supplement data slice within the storage system is received. A determination is made as to if the supplement data slice can be added within the storage system without defining a supplemental root slice for a storage system.

Abstract: A method is used in managing provisioning of storage in storage systems. Whether a logical object requires a slice for recovering the logical object is determined. Based on the determination, storage for the slice is provisioned. The slice is provided to the logical object.