Re: shutdown immediate or abort for cold-backup?

Talking of guessing what happens - have you run a trace/truss/tusc command to see what actually does happen ?

Your svrmgrl/sqlplus shadow sends a SIGKILL to all the current dedicated servers in turn, then does the same to the background processes in turn.

There is a great difference between sending SIGKILL to a process, and pulling the plug out of the back of the computer.

SIGKILL to a process does not cause the current, or previous call to the operating system to fail catastrophically - pulling the plug could leave disk heads spiralling in to crash on disks, scouring the surface clean, or at least sending a stream of electrical garbage down onto the disk.

Every time you do a shutdown abort, your filesystem is clean, your database files are clean, and the combination of data, control and redo log files are as consistent as they would be at any other instant of the database's life.

There is, however, one valid reason for not using 'shutdown abort' as a standard way of stopping the database: namely, very few people use it.

Because of this the recovery code will not have been tested at all the possible boundary conditions - the more times you do it, the greater your chance of being the first person to discover a 'special case' bug that causes recovery to fail.

In the same way, a shutdown immediate is more dangerous than a shutdown normal. The former requires Oracle to rollback any current transactions - again there may be some obscure boundary condition waiting to be discovered that results in a rollback failing and logically corrupting the database

--
Jonathan Lewis

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Scorpion wrote in message <3b8acdcd.47436757_at_news>...


>                If you do not work with a test DB or two,

>then you have no buisness guessing what happens.




>Look at it this way, how many times can you pull the plug out of the

>back of your computer while running ('aborting' the OS) before you

>start to suffer?