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catalog datacopy file very slow [message #682648]

Thu, 05 November 2020 00:38

otoce
Messages: 3
Registered: November 2020

Junior Member

Hi,

i'm backup guy, very little knowledge of oracle. We have datacopy file on nfs share (10g network), cataloged datafile copy is preaty slow from my point of view, around 5 per min. Is this normal, could it be faster with some tuning ?

thanks

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Re: catalog datacopy file very slow [message #682649 is a reply to message #682648]

Thu, 05 November 2020 00:47

Michel Cadot
Messages: 68716
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Most likely NFS issue.
Use "dd" to estimate its performances.

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Re: catalog datacopy file very slow [message #682657 is a reply to message #682648]

Thu, 05 November 2020 09:17

EdStevens
Messages: 1376
Registered: September 2013

Senior Member

Hard to say without knowing exactly what " datacopy file" or "datafile copy" actually is. Cannot comment on code I cannot see.

That said, it sounds like you might simply be copying (at an OS level) the data files of the database. If that is so, and your database is not shut down when you do that, then those backups are pretty much worthless, as the files will be inconsistent. Backing up a database is much more involved than backing up, say, a directory of Word documents. That's why oracle provides their 'rman' utility.

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Re: catalog datacopy file very slow [message #682665 is a reply to message #682657]

Fri, 06 November 2020 04:13

otoce
Messages: 3
Registered: November 2020

Junior Member

Hi,

thanks for answers. Little bit more on env.INC backup is done with rman (and first FULL also). After that INC is merged with FULL backup on Data domain, outside of rman knowledge. Then new full backup have to be reported to rman with:
catalog datafilecopy '/datadomain/xxx/SNAPSHOT/20201104-21:18:08/xxx_TS_xxx_DAT_FNO_73.bkp' TAG='xxx_FULL_20201104-21:18:08';

and this is very slow, 5 per min.

Server is heavy loaded so dd is also pretty slow to nfs and to local disk (san):

local disk:
for i in {1..10}; do time dd if=/dev/zero of=/localdisks/ttf/test$i.img bs=536870912 count=1 ;done
1+0 records in.
1+0 records out.

real 0m7.529s
user 0m0.001s
sys 0m0.954s
1+0 records in.
1+0 records out.

real 0m6.854s
user 0m0.000s
sys 0m0.979s
1+0 records in.
1+0 records out.

nfs:
for i in {1..10}; do time dd if=/dev/zero of=/nfs/xxx/temp/test$i.img bs=536870912 count=1 ;done
1+0 records in.
1+0 records out.

real 0m4.493s
user 0m0.001s
sys 0m0.946s
1+0 records in.
1+0 records out.

real 0m4.446s
user 0m0.001s
sys 0m0.879s
1+0 records in.
1+0 records out.

lsof |grep -c .
138808

[Updated on: Fri, 06 November 2020 04:14]

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