Re: Huge memory consumption during hot backup

Hello Howard,

   I tried to use the scripts you wrote
(http://www.dizwell.com/html/scripted_backups.html), but I'm experiencing the same available memory decrease (from 750 Mb to 250 Mb), while the scripts execute the "objFS.COPYFile strInput, strOutput" command on a 2 Gb datafile (I've about 10 datafiles sized 2 Gb).

I think that it is a problem related to Windows file cache management, even if I don't know how to manage it. As I wrote, I've already tried to change the the "File and Printer Sharing for Microsoft Networks" properties but with no success.

I'll try with RMAN ASAP...

Best regards,

Paolo Borghesi

"Howard J. Rogers" <hjr_at_dizwell.com> wrote in message news:<414a29d3$0$23896$afc38c87_at_news.optusnet.com.au>...
> Paolo wrote:
>
> > Hi,
> > I'm using Oracle 8.1.7.4.1 on Windows 2000 Advanced Server SP 3.
> > The DB is in archive log mode, and I use the following script to
> > perform an hot backup:
> >
> > -------------------------------------------------------
> > spool temp_bk_res
> > $SET backup=x:\backup
> > connect user/password_at_mydb as sysdba
> > $mkdir x:\backup\today
> > alter tablespace GENESYS_CFG begin backup;
> > $copy Y:\ORACLE\ORADATA\MYDB\USERS01.DBF x:\backup\today
> > alter tablespace GENESYS_CFG end backup;
> > alter tablespace GENESYS_LOG begin backup;
> > $copy Y:\ORACLE\ORADATA\MYDB\USERS02.ORA x:\backup\today
> > $copy Y:\ORACLE\ORADATA\MYDB\USERS02.ORA x:\backup\today
> > $copy Y:\ORACLE\ORADATA\MYDB\USERS02.ORA x:\backup\today
> > alter tablespace GENESYS_LOG end backup;
> > [...]
> > -------------------------------------------------------
> >
> > My problem is that when I begin the backup the available physical
> > memory decreases by around 400-500Mb, and if my system have less free
> > memory than requested it begins to swap a lot, making the database
> > unable to reply to the application (which hang).
> >
> > I've tried also by replacing the "$copy" commands with the "$start
> > /wait /low ocopy" commands, but the memory consumption has not
> > changed; besides, I tried to change Windows' file cache usage, by
> > setting the "File and Printer Sharing for Microsoft Networks"
> > properties to "Maximize data throughput for network applications", but
> > with no success.
> >
> > Do you have something to suggest?
> >
> >
> > Best regards,
> >
> > Paolo Borghesi
>
> What I'd *really* suggest is to use RMAN to do your backups.
>
> But if RMAN is absolutely not on, then I'd suggest having a look at the sort
> of Windows Scripting Host script I have available at
>
> http://www.dizwell.com/html/scripted_backups.html
>
> I've run that against many databases, and it doesn't have anything like the
> memory hit you are talking about.
>
> (As the site says, I hope: although the script has one 9i specific bit in
> it, it runs on 8i just fine so long as you edit the 21 lines bit to
> whatever is appropriate to 8i).
>
> I'd be interested, in any case, to see whether you can replicate your memory
> drop using it. If you can, something serious is up. If you can't then it's
> something in the script you are already using.
>
> Regards
> HJR
Received on Fri Sep 17 2004 - 10:29:12 CDT