Abstract: A host computer is configured to issue one or more unmap commands to a file system of a storage device, the file system being shared by a plurality of host computers including the host computer, by performing the steps of: acquiring unmap privilege information from the storage device, the unmap privilege information indicating whether or not an unmap privilege is available to the host computer; in response to determining that the unmap privilege is available, transmitting a request to update an unmap privilege file stored in the storage device to indicate that the host computer has the unmap privilege; and then issuing to the file system, the one or more unmap commands to deallocate storage space from one or more files of the file system.

Abstract: A host computer is configured to issue one or more unmap commands to a file system of a storage device, the file system being shared by a plurality of host computers including the host computer, by performing the steps of: acquiring unmap privilege information from the storage device, the unmap privilege information indicating whether or not an unmap privilege is available to the host computer; in response to determining that the unmap privilege is available, transmitting a request to update an unmap privilege file stored in the storage device to indicate that the host computer has the unmap privilege; and then issuing to the file system, the one or more unmap commands to deallocate storage space from one or more files of the file system.

Abstract: A method of synchronously executing input/output operations (IOs) for a plurality of applications using a storage device with a file system includes the steps of: receiving a first write IO including an instruction to write first data at a first address of the file system; determining that, within a first range of the file system comprising the first address, there are no pending unmap IOs for deallocating storage space of the storage device from files of the plurality of applications; after determining that there are no pending unmap IOs within the first range, locking the first range to prevent incoming unmap IOs from deallocating storage space within the first range from the files of the plurality of applications; after locking the first range, writing the first data to the storage device at the first address; and after writing the first data, unlocking the first range.

Abstract: An example method of handling, at a hypervisor on a host in a virtualized computing system, a write input/output (IO) operation to a file on a storage device having a virtual machine file system (VMFS) is described. The method includes: generating logical transactions for the write IO operation having updates to metadata of the VMFS for the file; estimating, for the logical transactions, common space reservations for those of the updates to common fields in the metadata for the file; estimating, for the logical transactions, exclusive space reservations for those of the updates to exclusive fields in the metadata for the file; batching the logical transactions into a physical transaction, which includes a single reservation of space in a journal of the VMFS based on the common space reservations and a reservations of space in the journal for each of the exclusive space reservations, respectively.

Abstract: A method of deleting a first pointer block of a plurality of pointer blocks of a file system from a storage device used by a plurality of applications, wherein the plurality of pointer blocks are each subdivided into sub-blocks, includes the steps of: determining that a first sub-block of the first pointer block is marked as being empty of any addresses of the file system at which storage space is allocated to files of the applications; determining that a second sub-block of the first pointer block has not been marked as being empty; in response to the determining that the second sub-block has not been marked as being empty, determining that the second sub-block does not contain any addresses of the file system at which storage space is allocated to the files of the applications; and deleting the first pointer block from the storage device.

Abstract: A method of synchronously executing input/output operations (IOs) for a plurality of applications using a storage device with a file system includes the steps of: receiving a first write IO including an instruction to write first data at a first address of the file system; determining that, within a first range of the file system comprising the first address, there are no pending unmap IOs for deallocating storage space of the storage device from files of the plurality of applications; after determining that there are no pending unmap IOs within the first range, locking the first range to prevent incoming unmap IOs from deallocating storage space within the first range from the files of the plurality of applications; after locking the first range, writing the first data to the storage device at the first address; and after writing the first data, unlocking the first range.

Abstract: A method of synchronously executing input/output operations (IOs) for a plurality of applications using a storage device with a file system includes the steps of: receiving a first write IO including an instruction to write first data at a first address of the file system; determining that, within a first range of the file system comprising the first address, there are no pending unmap IOs for deallocating storage space of the storage device from files of the plurality of applications; after determining that there are no pending unmap IOs within the first range, locking the first range to prevent incoming unmap IOs from deallocating storage space within the first range from the files of the plurality of applications; after locking the first range, writing the first data to the storage device at the first address; and after writing the first data, unlocking the first range.

Abstract: A method of deleting a first pointer block of a plurality of pointer blocks of a file system from a storage device used by a plurality of applications, wherein the plurality of pointer blocks are each subdivided into sub-blocks, includes the steps of: determining that a first sub-block of the first pointer block is marked as being empty of any addresses of the file system at which storage space is allocated to files of the applications; determining that a second sub-block of the first pointer block has not been marked as being empty; in response to the determining that the second sub-block has not been marked as being empty, determining that the second sub-block does not contain any addresses of the file system at which storage space is allocated to the files of the applications; and deleting the first pointer block from the storage device.

Abstract: An example method of handling, at a hypervisor on a host in a virtualized computing system, a write input/output (IO) operation to a file on a storage device having a virtual machine file system (VMFS) is described. The method includes: sorting, at the hypervisor, a scatter-gather array for the write IO operation into sets of scatter-gather elements, each of the sets including at least one scatter-gather element targeting a common file block address; resolving offsets of the sets of scatter-gather elements to identify a first scatter-gather array of transaction-dependent scatter-gather elements; generating logical transactions for the first scatter-gather array having updates to metadata of the VMFS for the file; batching the logical transactions into a physical transaction; and executing the physical transaction to commit the updates to the metadata of the VMFS on the storage device for the file.

Abstract: A method of synchronously executing input/output operations (IOs) for a plurality of applications using a storage device with a file system includes the steps of: receiving a first write IO including an instruction to write first data at a first address of the file system; determining that, within a first range of the file system comprising the first address, there are no pending unmap IOs for deallocating storage space of the storage device from files of the plurality of applications; after determining that there are no pending unmap IOs within the first range, locking the first range to prevent incoming unmap IOs from deallocating storage space within the first range from the files of the plurality of applications; after locking the first range, writing the first data to the storage device at the first address; and after writing the first data, unlocking the first range.

Abstract: A method of deleting a first pointer block of a plurality of pointer blocks of a file system from a storage device used by a plurality of applications, wherein the plurality of pointer blocks are each subdivided into sub-blocks, includes the steps of: determining that a first sub-block of the first pointer block is marked as being empty of any addresses of the file system at which storage space is allocated to files of the applications; determining that a second sub-block of the first pointer block has not been marked as being empty; in response to the determining that the second sub-block has not been marked as being empty, determining that the second sub-block does not contain any addresses of the file system at which storage space is allocated to the files of the applications; and deleting the first pointer block from the storage device.

Abstract: System and method for journaling metadata update transactions of file system operations use logical metadata update transactions to record metadata updates for a target file in response to file system operation requests at a file system of the system. A single physical metadata update transaction is generated by consolidating multiple logical metadata update transactions for the target file. The physical metadata update transaction is then written to a journal area of a physical storage.

Abstract: A method of deleting a first pointer block of a plurality of pointer blocks of a file system from a storage device used by a plurality of applications, wherein the plurality of pointer blocks are each subdivided into sub-blocks, includes the steps of: determining that a first sub-block of the first pointer block is marked as being empty of any addresses of the file system at which storage space is allocated to files of the applications, determining that a second sub-block of the first pointer block has not been marked as being empty; in response to the determining that the second sub-block has not been marked as being empty, determining that the second sub-block does not contain any addresses of the file system at which storage space is allocated to the files of the applications; and deleting the first pointer block from the storage device.

Abstract: An example method of handling, at a hypervisor on a host in a virtualized computing system, a write input/output (IO) operation to a file on a storage device having a virtual machine file system (VMFS) is described. The method includes: generating logical transactions for the write IO operation having updates to metadata of the VMFS for the file; estimating, for the logical transactions, common space reservations for those of the updates to common fields in the metadata for the file; estimating, for the logical transactions, exclusive space reservations for those of the updates to exclusive fields in the metadata for the file; batching the logical transactions into a physical transaction, which includes a single reservation of space in a journal of the VMFS based on the common space reservations and a reservations of space in the journal for each of the exclusive space reservations, respectively.

Abstract: An example method of handling, at a hypervisor on a host in a virtualized computing system, a write input/output (IO) operation to a file on a storage device having a virtual machine file system (VMFS) is described. The method includes: sorting, at the hypervisor, a scatter-gather array for the write IO operation into sets of scatter-gather elements, each of the sets including at least one scatter-gather element targeting a common file block address; resolving offsets of the sets of scatter-gather elements to identify a first scatter-gather array of transaction-dependent scatter-gather elements; generating logical transactions for the first scatter-gather array having updates to metadata of the VMFS for the file; batching the logical transactions into a physical transaction; and executing the physical transaction to commit the updates to the metadata of the VMFS on the storage device for the file.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for reclaiming one or more portions of storage resources in a computer system serving one or more virtual computing instances, where the storage resources in the computer system are organized in clusters of storage blocks. In one aspect, a method includes maintaining a respective block tracking value for each storage block that indicates whether a call to reclaim the storage block is outstanding; determining, from the block tracking values, a respective cluster priority value for each of the clusters based on a count of storage blocks in the respective cluster for which a call to reclaim is outstanding; and reclaiming a first portion of storage resources in the computer system in accordance with the cluster priority values.

Abstract: The systems described herein are configured to enhance the efficiency of memory usage and access in a VM file system data store with respect to allocating memory in large and small file block clusters using affinity metadata and propagating and maintaining the affinity metadata in support of the described allocation. In order to maintain affinity metadata of the large file block cluster, affinity generation values stored on the large file block cluster are read and cached affinity generation values for each small file block cluster are read from an in-memory cache associated with the large file block cluster. When the stored affinity generation values and the cached affinity generation values do not match, affinity metadata from all the small file block clusters associated with the large file block cluster is used to update the affinity metadata of the large file block cluster and the associated cache.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for reclaiming one or more portions of storage resources in a computer system serving one or more virtual computing instances, where the storage resources in the computer system are organized in clusters of storage blocks. In one aspect, a method includes maintaining a respective block tracking value for each storage block that indicates whether a call to reclaim the storage block is outstanding; determining, from the block tracking values, a respective cluster priority value for each of the clusters based on a count of storage blocks in the respective cluster for which a call to reclaim is outstanding; and reclaiming a first portion of storage resources in the computer system in accordance with the cluster priority values.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for reclaiming one or more portions of storage resources in a computer system serving one or more virtual computing instances, where the storage resources in the computer system are organized in clusters of storage blocks. In one aspect, a method includes maintaining a respective block tracking value for each storage block that indicates whether a call to reclaim the storage block is outstanding; determining, from the block tracking values, a respective cluster priority value for each of the clusters based on a count of storage blocks in the respective cluster for which a call to reclaim is outstanding; and reclaiming a first portion of storage resources in the computer system in accordance with the cluster priority values.

Abstract: The systems described herein are configured to enhance the efficiency of memory usage and access in a VM file system data store with respect to allocating memory in large and small file block clusters using affinity metadata and propagating and maintaining the affinity metadata in support of the described allocation. During storage of file data, an affinity identifier of the file data is determined. The affinity identifier is used to identify a large file block cluster and a small file block cluster within the identified large file block cluster. The file data is stored in the selected small file block cluster and affinity metadata of the selected small file block cluster is updated to reflect the storage of the file data.