Abstract: A system manages a log-structured file system (LFS) by: receiving an input/output (I/O) operation for the LFS, the I/O operation prompting a key to be added to a first node of a tree metadata structure, the tree mapping addresses in a first address space to addresses in a second address space; determining that addition of the key to the first node would exceed a maximum number of keys allowed in the first node; adding a second node to the tree based on the determining, the second node containing the key; moving a quantity of keys from the first node to the second node such that a total number of keys resulting in the second node is less than half of the maximum number of keys, minus one, configured to be stored in nodes of the LFS; and writing updates to the tree metadata structure within the LFS.

Abstract: The disclosure herein describes managing write requests in a multi-layer data store using prefetch threads. Prefetch requests received at the multi-layer data store are added to a prefetch request queue. A first prefetch thread obtains a first prefetch request and a second prefetch thread obtains a second prefetch request from the prefetch request queue. A memory cache is updated with first metadata of the first prefetch request by the first prefetch thread and with second metadata of the second prefetch request by the second prefetch thread, in parallel. After the memory cache is updated, a data bank in memory reaches a flush threshold and data in the data bank is written to a second data store, wherein the first metadata and second metadata in the memory cache are used to update a metadata structure with respect to the data written to the second data store.

Abstract: Systems and methods for inspection and repair of VSAN object metadata. A user-space indirection layer is maintained to map logical addresses of VSAN objects to physical memory addresses of their metadata. Commands may then be sent from the user space to distributed object manager (DOM) clients, with the physical addresses of metadata of objects to be inspected. DOM owners thus may bypass their own indirection layers to retrieve object metadata directly from received user commands. Retrieved information is then used to reconstruct and repair object metadata. Repaired metadata may be written back to the VSAN by transmitting a write request containing the physical address at which the repaired metadata is to be written. DOM owners may be placed in a specified mode in which received I/O instructions are ignored unless they are designated as being for metadata repair purposes, such as by including a physical address.

Abstract: System and method for managing distributed storage objects for host unavailability in a distributed storage system uses at least one of a crash indicator in a specific on-disk block and a paused object indicator for a distributed storage object to determine whether to perform data recovery for the distributed storage object. When the crash indicator is set or the paused object indicator implies that the distributed storage object is a paused object, the distributed storage object is left as a paused object without perform the data recovery for the distributed storage object. When the crash indicator is unset and the paused object indicator implies that the distributed storage object is not a paused object, the data recovery for the distributed storage object is performed.

Abstract: A method for metadata updating is provided. The method generally includes identifying a first segment containing a first physical block corresponding to a first PBA where content of a first data block was previously stored, determining a first key associated with the first data block, wherein the first key comprises a block address in a first key-value pair that maps the block address to the first PBA, traversing a B+ tree to locate a node storing a second key-value pair that maps the first key to a second PBA, determining the second PBA and the first PBA match, and based on the determination: updating, in the second key-value pair, the second PBA to a third PBA corresponding to a second physical block where the content of the first data block is currently stored or removing, in the second key-value pair, the second PBA.