Re: Sudden Backup Slowdown

Hi Nenad,
The only real difference between the AWR reports is that the statistic "RMAN cpu time (backup/restore)" is about 50% longer than before.  Sar shows the run queues as 0 (or close to 0) before and after the backup in both cases and similar during the backup (about 20-25). Thanks,Charlotte On Monday, November 4, 2019, 02:51:38 PM GMT, Noveljic Nenad <nenad.noveljic_at_vontobel.com> wrote:  

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Ifthere weren’t any idle CPUsduring backup, I’d first verify the statement “The server itself has no other activity during the backup window.” by measuring the length of the run queues. In other words, to confirm there aren’t any other processes competing for CPUs.  

What differences do you see in AWR reports?  

Best regards,  

Nenad  

https://nenadnoveljic.com/blog/  

From: oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org>On Behalf Of Charlotte Hammond Sent: Montag, 4. November 2019 15:22
To: ORACLE-L <oracle-l_at_freelists.org> Subject: Sudden Backup Slowdown  

Hello All,  

I'm trying to explain why my level 0 rman backups have suddenly jumped from 8hours to 12 hours.  The size of the backup has barely changed and there has been no configuration changes.  AWR and O/S statistics show that CPU for all the channels are maxed out at ~99% (presumably backup compression) for most of this time, both in the 8 hour case and 12 hour case.  The server itself has no other activity during the backup window.  

This is on 11.2.0.4 on AWS EC2 backing up to S3 storage.  

I'm not looking for tuning advise here (thanks though!) - I'm really hoping for some advise on finding an explanation for the change in times.  Given that all it's doing is sitting on CPU I'm not sure what else I can investigate - especially with limited ability to cross-reference it with the "good old" runs.   It's been 8 hours for months and months, and has now been 12 hours for the last 3 weeks.   There was no gradual increase - just a step change.  

Thanks!  

Charlotte  

  
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