Re: How can I estimate the size necessary for archive log files ?

Easy. Go out and buy the largest hard disk you can afford, and keep as many archives on it as it has room for. Also go and buy a nice DLT tape system, and use standard rotations to keep at least 3 months' of archives available (last time I did this for real, we could go back 6 months or so if we needed to).

Sorry... not being flippant, but archives are the only thing standing between you and data loss. You skimp on their storage at your dire peril. Theory states that you can dispose of prior archives as soon as a new backup is completed, but theory is a long way short of what happens in real life (failed backups, backups that included corruption, backups accidentally deleted, users wanting to restore data from weeks ago, and so forth).

Each archive log will be as big as your online redo log. You will produce a new archive every time you log switch. Work out how often you are log switching each day by checking the alert log ('thread 1 advanced to log sequence 373568' is the log switch). Multiply the two together, and that's a day's archives. Multiply by how many days' protection you deem appropriate.

Regards
HJR

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"Frederic Payant" <fpayant_at_club-internet.fr> wrote in message
news:sclq7ug0aaa5qmkg1skutglj3d4ifaqnsj_at_4ax.com...


> Hi,

>

> How can I estimate the size necessary for archive log files ?

>

> Thanks

> (it's for oracle 8.1.7 on Solaris 8, but I suppose that formula should

> work on any system)

> Regards

> Frederic PAYANT - junior DBA ;-)