## 24.2. Disk Full Failure

The most important disk monitoring task of a database administrator is to make sure the disk doesn't grow full. A filled data disk may result in subsequent corruption of database indexes, but not of the tables themselves. If the WAL files are on the same disk (as is the case for a default configuration) then a filled disk during database initialization may result in corrupted or incomplete WAL files. This failure condition is detected and the database server will refuse to start up.

If you cannot free up additional space on the disk by deleting other things, you can move some of the database files to other file systems by making use of tablespaces. See Section 18.6, “Tablespaces” for more information about that.

### Tip

Some file systems perform badly when they are almost full, so do not wait until the disk is completely full to take action.