Re: Files copy 5x faster when Oracle is running!

On 29 Apr 2002 12:07:14 -0700, sawics_at_hotmail.com (Steve Sawicki) wrote:

>Hello,
> Can any one tell me why when I attempt to copy datafiles within
>Solaris 2.7 from a RAID5 array to a striped array I see a 5x+
>performance increase only while oracle 8.1.6 is running? I wrote a
>script to copy all instance files (.dbf, .ctl, .ora & logs) and tested
>it while the instance was up. The goal is to copy all files to an
>offline volume for cold backups. When I down the instance and execute
>the script 31GB in 1:15 turns into 5GB/hour! The only diff is that the
>instance is up or down. What is going here?!?! Help! Need cold
>backups!
>
>Steve

The files are permanently open of course, once the database is started. Most likely the O/S caches the files, the Solaris file cache can be quite huge. To your disappointment probably: that file cache should be off, and the memory devoted to buffer cache. Depending on your config and money, special tools like RMAN and/or special backup products might do a better job than an ordinary cp

Hth

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Tue Apr 30 2002 - 07:12:18 CDT