RE: Recommended number of redo log switches per hour

On Thu, 14 Mar 2002, Khedr, Waleed wrote:

> In my opinion not less than 5-10 minutes in very busy times.

The three log switches per hour reccomendation from Oracle support is delusional. I would need 5 to 10 Gb logfiles to accomodate that reccomendation. And any standby would be miserably behind at all times. And recovery time (assuming log switch checkpoints) on instance failure would be unacceptable.

Wall clock time is a bad metric for this question, and support should not have told Patrice this.

If checkpoints are usually able to finish before the next log switch, then the logfile sizes are fine.

Robert F., Here's one for ya.

--
Jeremiah Wilton
http://www.speakeasy.net/~jwilton



> -----Original Message-----


> Sent: Thursday, March 14, 2002 8:19 AM

> To: Multiple recipients of list ORACLE-L

> 

> An Oracle Support technician recommended that I try to aim for three log

> switches per hour, during busy times.

> 

> According to the throughput I got yesterday between 3 and 4 o'clock PM, my

> redo log files would each have to be 1G in size.

> 

> That seems much too large to me, and I am not even sure it is possible to

> create redo log files that size.  Under Oracle 7.3. the largest I could

> create on Tru64 UNIX 4.0g was 40M redo log files.

> 

> Is this another "rule of thumb" that should go down the drain?


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Author: Jeremiah Wilton
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