Re: rman backup slow

  • From: Prasad <p4cldba@xxxxxxxxx>
  • To: ORACLE-L <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 30 Jan 2009 20:45:46 -0800

my apologies for the late response.     To answer this . not it is not a new
database . it has been in production since last couple of years.  it hosts a
application which has lot of LONG RAW data . it is right now 170GB . out of
which  the LONG RAW table only occupies 80GB.  The RMAN backup is taken
connected to recover catalog .  The backup goes to disk . right now the
cursor_sharing is set to similar .  The most significant wait I see is disk
async i/o  . This is a solaris server with vxfs and it do not support async
i/o .

The puzzling factor is the select on x$dual which just sits silently for
hours. and the entire backup duration goes beyond 10 hour .

This is what we are planning to do  increase the db_writer_process from 1 to
4  and set the disk_asynch_io to false ( i gues the default is TRUE) .
would appreciate your thoughts on this change .

because of the sensitivity of the application ( it is a highly visible
production database)  it is a bit hard to find time to take  a no catalog
backup  and also do any tracing experiment  .  but i guess it seems
unavoidable .

hopefully I didnt miss to provide any information asked. please feel free to
let me know if any further information will assist finding solution.

Thanks again .


> On Jan 30, 2009, at 1:10, Prasad <p4cldba@xxxxxxxxx> wrote:
> All,
> we have a 170G db on 9)  . and I see that it currently is
> taking nearly 10 hour+ to do a rman backup .  when I see this in grid
> control I see the rman session keeps waiting  on this sql .
> anyone has any similar situation .  appreciate any suggestion.
> Thanks in advance
> thanks
> Prasad

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