Vmware, Inc.

Srikanth Mahabalarao

Prasanna Aithal

Mahesh Shivanagouda Hiregoudar

Srinivasa Shantharam

Rohan Pasalkar

Prasad Rao Jangam

Pradeep H Krishnamurthy

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.

Avoiding data inconsistency in a file system using 2-level synchronization

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.

Journal space reservations for virtual disks in a virtualized computing system

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.

Optimal method for deleting sub-blocks of a pointer block that do not have on-disk metadata headers for addresses

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.

Write input/output optimization for virtual disks in a virtualized computing system

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.

The disclosure provides an approach for performing a write to a storage system, the write having reduced latency due to parallelism of sub-steps of the write, and due to calculating a partial rather than a full checksum. The mechanism of the write has low file corruption of files on the storage system, due to journaling of the checksum.

Enabling parallel IO's with partial checksum on imbricated journal slots

A method is provided for a computer to allocate a resource from a clustered file system (CFS) volume stored on one or more physical storage devices to a file. The CFS volume includes resources organized into resource clusters and the resource clusters make up regions. The method includes, for each region of resource clusters, determining a first count of resources allocated to the host computer and a second count of resources allocated to all other host computers, and calculating a region weight based on the first count and the second count. The method further includes sorting a list of the regions based on their region weights, selecting a region at or near the start of the list, and allocating the resource from a resource cluster in the selected region to the file.

Growing community of inventors

Bengaluru, India

Srikanth Mahabalarao