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ORACLE Instance *** - Can not allocate log, archival required

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Junghun
Occasional Advisor

ORACLE Instance *** - Can not allocate log, archival required

HI
When i was checking the alert_***.log to looking for the errors of oracle functioning,i found that the server failed to archive some of tbe archiving logs.Though the log was finally completed successfuly,i wander why it was failed first.i hope someone can tell me the problem which can cause archiving failure and what can i do to avoid the failure.
My server :alpha server ES45
os version:Tru 64 V5.1 B
oracle :oracle 8.1.7.4
Thanks
--Junghun
7 REPLIES
Michael Schulte zur Sur
Honored Contributor

Re: ORACLE Instance *** - Can not allocate log, archival required

Hi,

there is a note in metalink 119547.1
It says that as long as the redolog is successfully archived this messages can be ignored.

greetings,

Michael
Hein van den Heuvel
Honored Contributor
Solution

Re: ORACLE Instance *** - Can not allocate log, archival required


I see from the alert log that the system is checkpointing rapidly. Roughly once eveer 10 seconds. That may be a serious performance problem. Is that by design or by accident?
It may be a component of the archive problems... you are turning them over rapidly.

fwiw,
Hein.
Michael Schulte zur Sur
Honored Contributor

Re: ORACLE Instance *** - Can not allocate log, archival required

Hi,

I did not pay attention to the times.
Hein is right. If you switch redo logs too fast because they are too small then you get performance problems because with every switch there is a check point and all dirty blocks will have to be written to disk.

Michael
Junghun
Occasional Advisor

Re: ORACLE Instance *** - Can not allocate log, archival required

HI
Thanks both Michael and Hein.I will check the system checkpointing speed.But can you advise me what speed will be appropriate?
-Junghun
Hein van den Heuvel
Honored Contributor

Re: ORACLE Instance *** - Can not allocate log, archival required


'checkpoint speed' is an application choice, but far too many installations allow default parameters or age old file sizes to determine this.

I think 10 seconds is too fast except for extreme cases where the archived logs are shipped to a remote system to keep it up to date within 10 seconds.

Why not aim for 10 minutes or so?

Oracle allows you to set it by time, and space. Relevant init.ora params:

#LOG_CHECKPOINT_INTERVAL
#LOG_CHECKPOINT_TIMEOUT
#LOG_CHECKPOINTS_TO_ALERT
and with 9i, more interesting perhaps: MTTR= mean time to recover. Read all about it!

Often overlooked is the REDO file size.
Once it is full, a checkpoint will occur, and a new archive created.
Your choice there depends on the log block write speed. Let's say you write at 1mb/sec, and you accept my goal of 10 minutes. That would mean your redo log file needs to be sized at 10*60*1=600MB. If your redo log write speed was 10MB/sec (a mighty busy system!), you'd need 6GB redo logs for them not to control checkpointing.
For benchmarks we often play with 2 - 10 GB redolog to make sure they do not control the checkpoints, but we do with other means.
For production sites I suppose something in the 200MB - 1GB range often works, but 5MB or 10MB does not work well.

Anyway, this is really all Oracle stuff. Nothing much to do with Tru64. Just google for +oracle +"checkpoint interval" or such and you'll find tons of advice, some better than other. Or just check the Oracle Concepts or Tuning books? (What a concept!)

Hope this helps some,
Hein.
Michael Schulte zur Sur
Honored Contributor

Re: ORACLE Instance *** - Can not allocate log, archival required

Hein,

that sounds good what you write.
I remember from the training that when the next redo log switch occurs before the database writer has finished writing the dirty blocks to disk then you get into troubles.
See
http://www.rampant-books.com/t_ocpinstructors_112_checkpoint_.htm

Michael
Junghun
Occasional Advisor

Re: ORACLE Instance *** - Can not allocate log, archival required

HI
Both of u are good guys!Actually this is my first attempt to submit my problem in this forums and thanks for all of ur help!i have become SA two months ago,and i only have little knowledge of oracle.But i belief i will grow up soon,for i will work hard and guys like you will help me when i have problems.
thank you!
-Junghun