| Ideal size of Redo logfiles [message #268067] |
Mon, 17 September 2007 07:37  |
Aalap
Messages: 4
Registered: September 2007
Location: India
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Junior Member |
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Hello,
We were facing a problem with redo logs.
The alert file showed that the Redo logs were being switched very fast (approx every 2 mins).
Due to fast switching, it sometimes could not find an inactive log file and it gave the error of "Cannot allocate new log". The database became sluggish and users couldnt even connect.
We found a solution to it - keep increasing the size until the error goes away... we did it and it is working fine now...
Now we have 3 redo logfiles of size 300MB each.
The question is:
How can we estimate the best size of redo logfiles ?
Is "Trial and Error" the only best method to find the correct size?
Thanks in advance...
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| Re: Ideal size of Redo logfiles [message #268205 is a reply to message #268078] |
Mon, 17 September 2007 23:59  |
Aalap
Messages: 4
Registered: September 2007
Location: India
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Junior Member |
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Michel, Thanks for the note, we increased the size of redo logs and the problem got solved...
My question is - Is there an ideal size for redo logfiles? or are there any rules/queries to find the ideal size of redo logfiles ?
What are the sizes of redo logs in general ?
We have 12 servers and we can't keep doing trial & error on every server to find out the ideal size...
Thanks
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| Re: Ideal size of Redo logfiles [message #268719 is a reply to message #268715] |
Wed, 19 September 2007 08:05 |
NandKumar
Messages: 92
Registered: June 2007
Location: v$hyderabad
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Member |
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Iam afraid....No no need to create the database...You have to create new redo log files using
SQL> alter database add logfile group 4 'd:\nand\redo04.log' size 10m;
For dropping make sure the group is not the current/active one using the v$log view.
SQL> alter database drop logfile group 1;
will drop the logfile.
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| Re: Ideal size of Redo logfiles [message #268979 is a reply to message #268693] |
Thu, 20 September 2007 05:38 |
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
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Senior Member |
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There shouldn't be too much guessing involved for the sizing.
You can use the archive logs, or v$loghist to see when the logfiles switched. You know the size of the log files, so this will let you know how much Redo you are generating per hour. If you want to switch about 4 times an hour at most, size your logfiles to each be 1/4 the size of the Max redo generated per hour.
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