From: [EMAIL PROTECTED]

> in order to estimate the size of the log area I have to 
> define the backup cycle of the log devspaces. Which databse 
> parameter is to be set to do so?

The database performs an automatic log backup (also known as 
"autosave" or "autolog") if a so called "log segment" is full.

There is a configuration parameter LOG_SEGMENT_SIZE to set
a user defined size.
( http://www.sapdb.org/htmhelp/bd/a78658961511d5993300508b6b8b11/content.htm
)

It depends on the traffic in your database how long it
will take until a log segment is full.

> The documentation says it is recommendable to split the whole 
> log area in several log devspaces. Is there a "fist rule" 
> (estimation formula) to find out how many log devspaces one 
> should setup? Is this rule (split the whole data area into several
> devspaces) also valid for the data area?

As I know our documentation describes the splitting in
several devspaces as a feature not a recommendation. 
( http://www.sapdb.org/htmhelp/f2/790a7a490f11d5a9fb00a0c9449261/content.htm
)

You may split your data area in more than one devspace
located on different physical disks. So you may increase
the performance through parallel disc access.

But the log is written sequentially. So there is no 
effect due to the count of log devspaces.

Also there is no high availability advantage because
the log area (and also the data area) will be handled 
independent of the count of devspaces as one unit.

Bernd
-- 
SAP Labs Berlin
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