Abstract: The present disclosure is related to methods, systems, and machine-readable media for snapshot space reporting. A first probabilistic data structure can be created for a first snapshot of a virtual computing instance (VCI) in a file system based on a hash of physical block numbers of a plurality of blocks of the first snapshot. A second probabilistic data structure can be created for a second snapshot of the VCI based on a hash of physical block numbers of a plurality of blocks of the second snapshot. A space report can be determined for the first and second snapshots based on the first probabilistic data structure and the second probabilistic data structure, wherein the space report is indicative of the storage space occupied by the first and second snapshots. A file system function can be performed by reference to the space report.

Abstract: The present disclosure is related to methods, systems, and machine-readable media for file system event monitoring using metadata snapshots. A traditional snapshot of a virtual computing instance (VCI) can be created in a file system. The snapshot can correspond to an extent. An indication can be made that the extent is owned by a single snapshot. A metadata snapshot, corresponding to the extent, can be created without changing the indication that the extent is owned. The extent can be modified, wherein the indication that the extent is owned causes the extent to be modified without allocating a new extent.

Abstract: Techniques for efficiently managing a file clone from a filesystem which supports efficient volume snapshots are provided. In some embodiments, a system may receive an instruction to remove the file clone from the filesystem. The file clone may be a point-in-time copy of metadata of an original file. The system may further—for a file map entry in a filesystem tree associated with the file clone, the file map entry indicating a data block—decrement a reference count in a reference count entry associated with the file map entry. The reference count entry may be stored in the filesystem tree according to a key and the key may comprise an identification of the original file. The system may further reclaim the data block in a storage system when the reference count is zero.

Abstract: In one set of embodiments, a computer system can periodically run an unmap service configured to scan a subset of bitmaps maintained by a file system of the computer system. As part of scanning each bitmap in the subset, the unmap service can, for each bit in the bitmap: (1) check whether the bit indicates that a corresponding physical block address (PBA) on the storage backend is currently free; (2) upon determining that the bit indicates the PBA is currently free, identify an extent within the bitmap where the PBA resides; (3) check whether an unmap indicator associated with the extent indicates that at least one free PBA in the extent is not currently unmapped in the storage backend; and (4) upon determining that the unmap indicator indicates at least one free PBA in the extent is not currently unmapped in the storage backend, add the PBA to a list of PBAs to be unmapped.

Abstract: In one example, a method for writing data includes receiving a write request and performing a first type of logging process in connection with the write request, and creating a corresponding first logging record. Additionally, a second type of logging process is performed in connection with the write request, and a corresponding second logging record created, where the second type of logging process is different from the first type of logging process. Next, a determination is made, as between the two logging records, which of the logging records requires the least amount of non-volatile random access memory (NVRAM), and the logging record that requires the least amount of NVRAM is written to the NVRAM.

Abstract: In one example, a method for writing data includes receiving a write request and performing a first type of logging process in connection with the write request, and creating a corresponding first logging record. Additionally, a second type of logging process is performed in connection with the write request, and a corresponding second logging record created, where the second type of logging process is different from the first type of logging process. Next, a determination is made, as between the two logging records, which of the logging records requires the least amount of non-volatile random access memory (NVRAM), and the logging record that requires the least amount of NVRAM is written to the NVRAM.

Abstract: In one example, a method for writing data includes receiving a write request and performing a first type of logging process in connection with the write request, and creating a corresponding first logging record. Additionally, a second type of logging process is performed in connection with the write request, and a corresponding second logging record created, where the second type of logging process is different from the first type of logging process. Next, a determination is made, as between the two logging records, which of the logging records requires the least amount of non-volatile random access memory (NVRAM), and the logging record that requires the least amount of NVRAM is written to the NVRAM.

Abstract: In one example, a method for writing data includes receiving a write request and performing a first type of logging process in connection with the write request, and creating a corresponding first logging record. Additionally, a second type of logging process is performed in connection with the write request, and a corresponding second logging record created, where the second type of logging process is different from the first type of logging process. Next, a determination is made, as between the two logging records, which of the logging records requires the least amount of non-volatile random access memory (NVRAM), and the logging record that requires the least amount of NVRAM is written to the NVRAM.

Abstract: According to some embodiment, a storage system selects one or more directories within a file system as candidates for caching based on directory statistics associated with the directories, where each of the directories includes one or more file objects stored in the storage system. For each of the selected directories, the system determines whether the directory is to be cached based on a directory cache policy. The system caches the directory in a cache memory device in response to determining that the directory is to be cached.

Abstract: Embodiments are described for a method and system for improving B+Tree scan performance by receiving a data access instruction that specifies pages to be accessed in a data store utilizing a B+Tree data structure; defining a read-ahead context comprising an array of page numbers corresponding to the specified pages; loading the read-ahead context array into a read-ahead cache; and reading the first page of the read-ahead context in a synchronous manner, and each of the subsequent pages of the read-ahead context in an asynchronous manner.

Abstract: A small file storage system reduces the cost of storing and reading segmented data in a deduplication storage system. A data-blocking scheme is used to store small files instead of generating different levels of metadata as is done for larger files in deduplication systems. Among other advantages, the data blocking scheme reduces the cost of reading metadata segments from the content store, reduces the cost of index lookup, CM region read and decompression, and the cost of recalling and restoring small files from cloud storage, all of which contribute to better read performance. Other advantages include faster verification of small files, and improvements in small file data locality on disk with larger segment sizes. By eliminating the need to update metadata segments, embodiments of the small file storage system advantageously increase the efficiency of file updates, especially since updates to smaller files are more random in nature.

Abstract: In one embodiment, a method implementing file name based command execution is disclosed. The method includes periodically examining a predetermined file directory in a storage system to determine if the predetermined file directory contains any file. The method includes, upon finding a first file, determining that a file name of the first file includes one or more commands of a plurality of preconfigured commands executable in the storage system. The method includes executing the one or more commands included in the file name of the first file to perform one or more actions associated with the one or more commands. The method further includes creating a second file in the predetermined file directory, indicating that the included one or more commands are being executed. The method further includes that, upon that the one or more included commands finish execution, removing the first and second file from the predetermined file directory.

Abstract: Methods and apparatus to facilitate concussion screening are disclosed. Example apparatus disclosed herein include a housing, a mobile device bracket, a first mirror, a second mirror, and a light source. The housing has a viewing port. The mobile device bracket is disposed in the housing and configured to support a mobile device that has a display and a camera. The first mirror is disposed in the housing to reflect the display toward the viewing port. The second mirror is disposed in the housing to reflect the viewing port toward the camera. The light source is disposed in the housing.

Abstract: In one embodiment, a computer-implemented method includes capturing a consistent state of data blocks in a namespace cache of a deduplicating storage system. The data blocks contains data for a file system namespace organized in a hierarchical data structure. Each leaf page of the hierarchical data structure contains one or more data blocks. The method further includes determining, for each data block, whether the data block has been written to base on the captured consistent state. For at least one of the written data blocks in the namespace cache, the method includes searching, in the hierarchical data structure, adjacent data blocks to find in the namespace cache one or more data blocks that have also been written to, and upon finding the one or more adjacent written data blocks, flushing the written data block and the found one or more adjacent written data blocks together into a common storage unit.

Abstract: In some embodiments, in response to receiving an indication to warm up a SSD cache, a system identifies namespace data of a file system to be warmed up separated from content data. The system identifies one or more namespace pages of the namespace data. For each of the one or more namespace pages, the system locks the namespace page in a read-only mode and determines if the namespace page is dirty. If the namespace page is dirty, the system releases the namespace page from the read-only mode without copying the namespace page to the SSD cache. If the page is clean (i.e., not dirty) then the system copies the namespace page to the SSD cache and releases the namespace page from the read-only mode to reduce cache misses of the namespace on the SSD cache.

Abstract: A first data is stored in a first filesystem data storage, wherein the first filesystem data storage is part of a first cluster node that comprises a common filesystem metadata. A second data is stored in a second filesystem data storage, wherein the second filesystem data storage is part of a second cluster node coupled with the first cluster node that comprises the common filesystem metadata. The first cluster node and the second cluster node are associated with a cluster for shared storage.

Abstract: A computer-implemented method is implemented to compress a file system namespace. The method starts with determining that a first leaf page of a hierarchical data structure of a storage system is sparse. The hierarchical data structure contains root node layer, intermediate node layer, and leaf page layer, where each leaf page contains namespace entries corresponding to a file or a directory of a file system, and where being sparse means a first size of the entries of the first leaf page is less than a first percentage. The method continues with identifying a second immediate adjacent leaf page as a merging candidate. The method continues with merging the second leaf page into the first leaf page upon determining that a second size of combined entries of the first and second leaf pages is less than a second percentage larger than the first percentage.

Abstract: In one embodiment, a method includes creating a first number of streams for a file system manager of a deduplicating storage system to access concurrently a type of data blocks, where each stream is for one file system and is identified by a stream identifier. The method further includes mapping stream identifiers to each of the type of data blocks passing through the first number of streams. The method further includes accessing the type of data blocks in storage units of the deduplicating storage system through a second number of streams, where the second number of streams are dedicated to the type of data blocks in the deduplicating storage system, where the second number is smaller than the first number, where the data blocks are tracked according to the mapped stream identifiers, and where the data blocks are stored in the storage units after a deduplication process to remove duplication.

Abstract: A computer-implemented method of replicating a file system is disclosed. The method starts with receiving a source file system container map at a target storage system, the source file system container map including mapping between a source file system and containers containing data of the source file system. An active target file system container map is then created based on the source file system container map to map data of the source file system to containers of the target storage system storing the data of the source file system. The data corresponding to the containers mapping to the source file system are received. The active target file system container map is then populated as containers of the target storage system are populated with data from the deduplicated source storage system, wherein the source and target container maps are utilized in subsequent restoration of data of the source file system.

Abstract: A computer-implemented method to compress log messages is disclosed. The method starts with maintaining a log reference table having a plurality of log reference entries, each containing a string of characters to be recited repeatedly during logging of messages. In response to a request for logging a log message initiated from an application, the method creates a compressed log message entry in a compressed log file. The compressed log message entry includes: a time stamp indicating the time the log message being created; a log reference identifier identifying one of the plurality of log reference entries without reciting a corresponding string of characters of the log reference entry, where the one of the plurality of log reference entries contains one or more variable indications; and a log variable portion associated with the log message, where the log variable portion contains a part of the log message.