The Aspera Watch Service Automatically detect file system changes with the Aspera Watch Service. Starting Aspera Watch Services and Creating Watches The Aspera Watch Service (asperawatchd) is a file system change detection and snapshot service that is optimized for speed, scale, and distributed sources. On file systems that have file system notifications, changes in source file systems (new files and directories, deleted items, and renames) are detected immediately, eliminating the need to scan the file system. On file systems without file notifications, such as object storage, Solaris, AIX, and Isilon, file system scans are automatically triggered. Watch Service Configuration The Aspera Watch Service configuration in the <server> section of aspera.conf includes the snapshot database, snapshot frequency, and logging: Setting Custom Watch Scan Periods When a new subscription to a watch is created, it uses the default scan period of 30 minutes unless otherwise specified. You can also modify the scan period of an existing subscription. Managing Watch Subscriptions The Aspera Watch Service can watch the entire area of the file system to which the user has access. Individual watches are created by subscribing to the service and specifying a portion of the file system to watch. Each subscription can specify a scan period, database, and subscription expiration. When subscriptions overlap in the file system, the shortest scan period is used to scan the shared area. Transferring and Deleting Files with the Aspera Watch Service When used in conjunction with ascp commands, the Aspera Watch Service (asperawatchd) allows for fast detection and sending of new and deleted items. By comparing snapshots of the file directory it is watching, asperawatchd generates file lists for ascp transfers.