Oracle: log file group member

Status

An individual group member (a log file) can have one of the following states:

`INVALID`	A log file that cannot be written to by Oracle Log Writer (LGWR) background process
`STALE`	File's contents are incomplete
`DELETED`	File is no longer used
`null`	File is in use

select
   status,
   …
from
   v$logfile;