Understanding Space Watcher

Space Watcher Functionality

Space watcher is a background process that checks the amount of free space in the database and gives warning when space is running low.Once a minute, space watcher runs a ls or dir command, then writes the free space in bytes to a table named aspera_db_disk_space_free. The exact command it executes is:
df -k -P "aspera_console_db_directory_path"
It only writes one record, always with "id=1". The aspera_db_disk_space_free table will never have more than one record in it. This table only has three fields:
Field Value
id Always equal to 1.
bytes_free BIGINT, max value = 9223372036854775807, which is approximately 8191 petabytes
last_reported_at The time space watcher last stored an entry in the table.
If the process fails to figure out free space for any reason or fails to connect to MySQL, it does nothing and logs nothing. Successful or not, it then closes its connection and then sleeps for a minute before repeating the process.

Space Watcher Messages in Console

Unless warnings have been disabled (by setting the warning threshold to zero), Console checks the aspera_db_disk_space_free table when rendering a page. If it sees that there are no records in the table, or that it has been longer than 10 minutes since space watcher last reported, Console displays the following message at the top of the page: "WARNING: No recent data from database free space watcher". If the last entry is recent (within 10 minutes) but the number of free bytes is less than the configured warning level (default: 10 gigabytes), it shows a message such as the following: "WARNING: Database free space low (7.5 GB remaining)".