Hi,
On one of our database ,there is RMAN differential incremental backup strategy.
On Wednesday there was level 1 backup, but BAckup failed due to following errors:
RMAN-03009 - Failure of backup commnand
ORA-19502 - Write error on file
ORA-27072 - skgfdisp : I/O error
OSD-04008 - Write file() failure unable to write to file.
O/S error : (OS 121) The semophore timeout period has expired.

Can u please tell why this error occured? What does mean OS 121 error and how to fix it?

Thanks in advance.

Urgent help is highly appriciable.