RE: [EXTERNAL] Re: rman backup slow even after patching it

We match RMAN Backup is Slow after 19.11 Release Update (Doc ID 2846457.1), however, we did the suggested changes with no effect

From: David Barbour <david.barbour1_at_gmail.com> Sent: Monday, August 22, 2022 11:20 AM
To: gogala.mladen_at_gmail.com
Cc: Beckstrom, Jeffrey <jbeckstrom_at_gcrta.org>; mwf_at_rsiz.com; oracle-l_at_freelists.org Subject: Re: [EXTERNAL] Re: rman backup slow even after patching it

What is your backup target? Source media? Third-party backup application? We had a problem with backing up to Oracle Cloud after moving to 19.15 and the solution turned out to be re-installing the Oracle Database Cloud Backup Module . Seems there is a mismatch with the older oci interface. I wouldn't bet against a similar issue with the libraries in 19.14.

On Tue, Aug 16, 2022 at 10:38 AM Mladen Gogala <gogala.mladen_at_gmail.com<mailto:gogala.mladen_at_gmail.com>> wrote: On 8/16/22 09:44, Beckstrom, Jeffrey wrote:

In a rare factual error my friend Mladen missed that the list is ascending.

Still probably a network issue. Smirk. Unless that is backup & recovery read time (The key thing that *might* tell you a *lot* would be separation of I/O into I and O). I cannot remember their detailed description of this event and I'm too lazy to too it up. But I did re-arrange the output for that one line into "What" and useful "How much" columns.

Notice that the "also ran" second place was only about a minute of total wait. So this one bundled line for I and O is pretty much everything. So 41 milliseconds per I/O and I have no idea what a raw system level I/O between your source system and backup system is, or what size RMAN's I/O unit is (min, max, average) as configured. If you have some idea of the total bytes written, you could do a system to system level I/O of that size (maybe a bundle of 100 or 1000 repeats, so any possible begin and end process time error is minimized) and get a clue whether I/O time between systems is the problem, rather than something more complex inside Oracle.

Of course, Mark is right. I am using similar kind of query with "DESC" option for the ordering so I assumed that Jeff does the same. Apparently, my assupmtion was wrong. Not only that, rman network communication doesn't use SQL*Net, so the "SQL Net data to client" message is unlikely to be caused by rman. It might, however, be indicative of a network problem. My advice would be to also check disk I/O and network throughput using the Linux tools like atop, iotop and iptraf-ng. Even strace can be useful in this situation. Also useful are "perf" tools, like "perf top" and system wide profilers like "oprofile".

You may need to open a case with Oracle or your backup vendor.

Regards

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Mladen Gogala

Database Consultant

Tel: (347) 321-1217

https://dbwhisperer.wordpress.com<https://gcc02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdbwhisperer.wordpress.com%2F&data=05%7C01%7Cjbeckstrom%40gcrta.org%7C327f81ab2da9488ca86308da8451e045%7Cebe8e20736ec47f48cb8f5f757605f5d%7C1%7C0%7C637967784471206749%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=YEkMHYawIt6Al42ORVHoVwtsg5W31IYcFLeKvOtVf58%3D&reserved=0>

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http://www.freelists.org/webpage/oracle-l Received on Tue Aug 23 2022 - 13:41:46 CEST