Re: Swapping causing RMAN controlfile snapshot to fail?

From: Chris Taylor <christopherdtaylor1994_at_gmail.com>
Date: Wed, 4 Sep 2013 12:45:39 -0500
Message-Id: <D6592094-546C-412E-9AC9-06F5F9E69FD1_at_gmail.com>

Thats exactly what would happen if a backup is occurring at the OS layer on the filesystem you need to backup a file on.

Chris

Sent from my mobile device. Please ignore any typos.

On Sep 4, 2013, at 11:22 AM, "Rich Jesse" <rjoralist3_at_society.servebeer.com> wrote:

> Hey all,
>
> In 11.2.0.3 under AIX 5.3 TL12, I had a one-time RMAN error where it failed
> to snapshot the controlfile after a scheduled archive log backup:
>
> RMAN-03009: failure of Control File and SPFILE Autobackup command on
> ORA_DISK_1 channel at 08/03/2013 02:10:10
> ORA-01580: error creating control backup file
> /u01/app/oracle/product/11.2.0/db_1/dbs/snapcf_xxxxx.f
> ORA-27041: unable to open file
> IBM AIX RISC System/6000 Error: 22: Invalid argument
> Additional information: 4
>
> I opened an SR and the tech saw this in the alert.log:
>
> WARNING: Heavy swapping observed on system in last 5 mins.
> pct of memory swapped in [6.25%] pct of memory swapped out [11.01%].
>
> So, the tech surmised that the RMAN failure was due to swapping ("paging" in
> AIX land). Huh? That seems to be the opposite of the intent of paging,
> which is to keep programs running during memory pressure. Here's some more
> AIX info:
>
> minperm%=5
> maxperm%=90
> maxclient%=90
> lru_file_repage=0
>
> nmon reports the FileSystemCache usually around 12%, PageSpace at about 13%
> used (1.7GB of 12.8GB).
>
> When this failure occurred, a mksysb root VG backup kicked off. That
> apparently is the cause of the paging spike, as it happens every time mksysb
> runs. And it so happens that the controlfile snapshot is on the root VG (on
> purpose!). So my theory is that RMAN just happened to hit the controlfile
> snapshot at the exact same time that mksysb had a hold of the old one,
> although I can find no documentation to backup that behavior nor to discount
> it.
>
> Thoughts?
>
> TIA!
> Rich
>
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> http://www.freelists.org/webpage/oracle-l
>
>

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Received on Wed Sep 04 2013 - 19:45:39 CEST