Oracle error
ORA-01157
ORA-01157: cannot identify/lock data file %s - see DBWR trace file
What usually causes it
DBWR can't find or open a datafile: it's missing, renamed, has the wrong permissions, or its file system or ASM disk group isn't mounted.
What to check first
Restore access to the file or mount its storage. If the file is lost, restore and recover it with RMAN. A missing tempfile can simply be dropped and added again.
Scripts that help
- Datafiles with size and autoextend limitsEvery datafile, its current size, whether it can grow, and how far. Files with AUTOEXTEND NO in a busy tablespace are the ones that page you at night.
- ASM disk group spaceSize, free and usable space per disk group. Usable GB already accounts for mirroring, so it's the number to alert on. Works from the ASM or database…
- Alert log errors in the last 24 hoursORA- and TNS- errors plus checkpoint warnings from the alert log, read through SQL. It can be slow when the alert log is very large.