Abstract: An LL server (LLS) may process metadata requests for a file system in LL mode in a distributed file storage services (DFSS). For requests that require allocating blocks to file system objects in the backing store, instead of relying on distributed transactions used for file systems in high throughput (HT) mode, a pool of blocks may be pre-allocated for the LL file system in the backing store, and a free block list may be maintained in local memory of the LLS. When a metadata operation requires blocks to be allocated, the blocks are assigned to the respective object from the blocks in the pool. A background process may allocate new blocks in the pool upon the number of blocks dropping below a threshold, or upon block allocation rate for the file system increasing.

Abstract: An LL server (LLS) may process metadata requests for a file system in LL mode in a distributed file storage services (DFSS). For requests that require allocating blocks to file system objects in the backing store, instead of relying on distributed transactions used for file systems in high throughput (HT) mode, a pool of blocks may be pre-allocated for the LL file system in the backing store, and a free block list may be maintained in local memory of the LLS. When a metadata operation requires blocks to be allocated, the blocks are assigned to the respective object from the blocks in the pool. A background process may allocate new blocks in the pool upon the number of blocks dropping below a threshold, or upon block allocation rate for the file system increasing.

Abstract: A computing resource service provider may operate a data storage service configured to provide data storage for one or more customers of the computing resource service provider. The data storage service may store customer data in one or more replicated state machines, where the replicated state machines comprise a plurality of replicated state machine-shards. The replicated state machine-shards may cause the computer system hosting the replicated state machine-shard to transmit a consensus message to other computer system. The consensus message may include utilization information corresponding to the other computer system. The utilization information may be used to calculate a utilization rate for the replicated state machine usable in block allocation operations.

Abstract: A distributed file storage services (DFSS) that provides low latency (LL) and high throughput (HT) modes for file systems. A HT metadata subsystem (HTMS) may use a distributed transaction system for data and metadata reads and writes for file systems in HT mode. A LL metadata subsystem (LLMS) may process metadata requests for file systems in LL mode. For metadata read requests, the LLMS may locally cache at least some of the file system metadata. For metadata write requests, the LLMS may write entries to a journal and notify the access node after the entries are committed to the journal. Data reads and writes for file systems in LL mode may be handled similarly to data reads and writes for file systems in HT mode. A file system may be converted from LL to HT mode, or from HT to LL mode.

Abstract: An LL server (LLS) may process metadata requests for a file system in LL mode in a distributed file storage services (DFSS). For requests that require allocating blocks to file system objects in the backing store, instead of relying on distributed transactions used for file systems in high throughput (HT) mode, a pool of blocks may be pre-allocated for the LL file system in the backing store, and a free block list may be maintained in local memory of the LLS. When a metadata operation requires blocks to be allocated, the blocks are assigned to the respective object from the blocks in the pool. A background process may allocate new blocks in the pool upon the number of blocks dropping below a threshold, or upon block allocation rate for the file system increasing.

Abstract: A computing resource service provider may operate a data storage service configured to provide data storage for one or more customers of the computing resource service provider. The data storage service may store customer data in one or more replicated state machines, where the replicated state machines comprise a plurality of replicated state machine-shards. The replicated state machine-shards may cause the computer system hosting the replicated state machine-shard to transmit a consensus message to other computer system. The consensus message may include utilization information corresponding to the other computer system. The utilization information may be used to calculate a utilization rate for the replicated state machine usable in block allocation operations.

Abstract: A low latency metadata subsystem for file systems in low latency (LL) mode in a distributed file storage service (DFSS). An LL server (LLS) may receive metadata requests from an access node of the DFSS. For read operations, the LLS may check a local cache of metadata and, for cache hits, retrieve the metadata from the cache. For cache misses, the metadata may be fetched from the storage subsystem of the DFSS and cached. For write operations, the LLS may write entries into a journal for the file system and notify the access node after the journal entries are committed to the journal; the journal entries are asynchronously committed in the storage subsystem. The access node may communicate with the storage subsystem to perform data reads and writes for the LL file system.

Abstract: A computing resource service provider may operate a data storage service configured to provide data storage for one or more customers of the computing resource service provider. The data storage service may store customer data in one or more replicated state machines, where the replicated state machines comprise a plurality of replicated state machine-shards. The replicated state machine-shards may cause the computer system hosting the replicated state machine-shard to transmit a consensus message to other computer system. The consensus message may include utilization information corresponding to the other computer system. The utilization information may be used to calculate a utilization rate for the replicated state machine usable in block allocation operations.

Abstract: A computing resource service provider may operate a data storage service configured to provide data storage for one or more customers of the computing resource service provider. The data storage service may store customer data in one or more replicated state machines, where the replicated state machines comprise a plurality of replicated state machines-shards. The replicated state machines-shards may cause the computer system hosting the replicated state machine-shard to transmit a consensus message to other computer system. The consensus message may include utilization information corresponding to the other computer system. The utilization information may be used to calculate a utilization rate for the replicated state machine useable in block allocation operations.

Abstract: A low latency metadata subsystem for file systems in low latency (LL) mode in a distributed file storage service (DFSS). An LL server (LLS) may receive metadata requests from an access node of the DFSS. For read operations, the LLS may check a local cache of metadata and, for cache hits, retrieve the metadata from the cache. For cache misses, the metadata may be fetched from the storage subsystem of the DFSS and cached. For write operations, the LLS may write entries into a journal for the file system and notify the access node after the journal entries are committed to the journal; the journal entries are asynchronously committed in the storage subsystem. The access node may communicate with the storage subsystem to perform data reads and writes for the LL file system.

Abstract: An LL server (LLS) may process metadata requests for a file system in LL mode in a distributed file storage services (DFSS). For requests that require allocating blocks to file system objects in the backing store, instead of relying on distributed transactions used for file systems in high throughput (HT) mode, a pool of blocks may be pre-allocated for the LL file system in the backing store, and a free block list may be maintained in local memory of the LLS. When a metadata operation requires blocks to be allocated, the blocks are assigned to the respective object from the blocks in the pool. A background process may allocate new blocks in the pool upon the number of blocks dropping below a threshold, or upon block allocation rate for the file system increasing.

Abstract: A distributed file storage services (DFSS) that provides low latency (LL) and high throughput (HT) modes for file systems. A HT metadata subsystem (HTMS) may use a distributed transaction system for data and metadata reads and writes for file systems in HT mode. A LL metadata subsystem (LLMS) may process metadata requests for file systems in LL mode. For metadata read requests, the LLMS may locally cache at least some of the file system metadata. For metadata write requests, the LLMS may write entries to a journal and notify the access node after the entries are committed to the journal. Data reads and writes for file systems in LL mode may be handled similarly to data reads and writes for file systems in HT mode. A file system may be converted from LL to HT mode, or from HT to LL mode.

Abstract: A node of a distributed storage service receives a read request from a client, directed to a particular physical page storing at least a portion of a file store object. The node transmits, to the client, a particular operation sequence number (OSN), obtained from a replicated state machine, indicative of an order in which the read request was processed at the node relative to other requests directed to the file store object. The node receives a write request from the client directed to the page. The write request includes the particular OSN. The node determines whether the page has been modified after the particular OSN was obtained. If the page has not been modified since the OSN was obtained, a modification indicated in the write request is performed; otherwise, the write request is rejected.