Re: log file size

ARCHIVE_LAG_TARGET should take care of that. 4GB redo log saves the day only in the situation in which there is a log switch every minute or two. ARCHIVE_LAG_TARGET will force switch even if the redo log is not full yet.
Regards

On 10/16/2017 03:19 PM, Reen, Elizabeth wrote:
> Another thing to look at is the transfer rate of your network. You want as many logs to get over to the DG environment as possible.
>
>
> Liz
>
> Elizabeth Reen
> CPB Database Group Manager
> 718.248.9930  (Office)
> Service Now Group: CPB-ORACLE-DB-SUPPORT
>
>
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Mladen Gogala
> Sent: Monday, October 16, 2017 10:53 AM
> To: oracle-l_at_freelists.org
> Subject: Re: log file size
>
> Hi Orlando,
>
> There is not theoretical size limits to your redo log files. If you have enough storage, you can make your redo log size 1PB each. However, the larger your redo log files are, the longer it will take to apply them.
> 4GB is a normal redo size for OLTP databases with a lot of concurrent transactions. I have even encountered 16GB redo logs at one large bank.
> However, I would advise setting log_checkpoint_timeout to induce a checkpoint at least once every 10 minutes. That way, you will only need to recover last 10 minutes, no matter how large your redo log files are.
>
> Regards
>
> PS:
>
> ----
>
> If you opt for 1PB log files, please let me know. I would be very curious about that.
>
>
>
> On 10/16/2017 02:02 AM, Orlando L wrote:
>> Hello,
>>
>> I recently inherited a prod DB; one of the things I noticed was that
>> it was doing log switches around 15 times a minute (not one hour). I
>> did some calculation based on the log sizes and I came up with a size
>> of 4 Gb per log for less frequent switches. Is there any limitations
>> fellow oraclites can think of in setting the online log files high.
>> One thing I can think of archiver delay locally and standby lag, if
>> any, in case if the switches slow down.
>> Orlando.

-- 
Mladen Gogala
Oracle DBA
http://mgogala.freehostia.com

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