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Restore time 15x backup time [message #130363]

Fri, 29 July 2005 09:51

Slow Poke
Messages: 7
Registered: July 2004

Junior Member

I am using Oracle 9.2.0.6 on Windows 2000 with Vertias NetBackup 5.1. It takes about 10-12 minutes to backup the database which is about 4-5GB in size. I did a full database restore and it takes about 2hours and 50 minutes to complete the restore and recover. Are there any parameters that can be changed to speed this up? I know that restores take longer than backups, but this doesn't seem right for this size of database. I used two channels.

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Re: Restore time 15x backup time [message #130366 is a reply to message #130363]

Fri, 29 July 2005 10:03

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

Post your RMAN configuration (show all command from RMAN prompt),backup/restore scripts

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Re: Restore time 15x backup time [message #130369 is a reply to message #130363]

Fri, 29 July 2005 10:20

Slow Poke
Messages: 7
Registered: July 2004

Junior Member

Here is an extract of my script with the RMAN code:

echo RUN {
echo ALLOCATE CHANNEL ch00 TYPE 'SBT_TAPE';
echo ALLOCATE CHANNEL ch01 TYPE 'SBT_TAPE';
echo RESTORE
echo DATABASE;
echo RECOVER
echo DATABASE;
echo sql 'alter database open';
echo RELEASE CHANNEL ch00;
echo RELEASE CHANNEL ch01;
echo }
) | %RMAN% target %TARGET_CONNECT_STR% nocatalog msglog '%RMAN_LOG_FILE%' append

Here is the RMAN log:

=== started on Thu 07/28/2005 10:35a ====
Script name: full_db_restore_LSAtest
#
RMAN : d:\oracle\ora92\bin\rman.exe
NLS_LANG : american
ORACLE_HOME : d:\oracle\ora92
ORACLE_SID : lsa
TARGET_TNS : lsa
RCVCAT_TNS :
NLS_DATE_FORMAT : YYYY-MM-DD:hh24:mi:ss
RMAN_LOG_FILE : "D:\ORACLE\LSA\coldLSA_dbrestore-07282005 .log"

Recovery Manager: Release 9.2.0.6.0 - Production

Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.

connected to target database: LSA (DBID=2029962587)
using target database controlfile instead of recovery catalog

RMAN> 2> 3> 4> 5> 6> 7> 8> 9> 10> 11>
allocated channel: ch00
channel ch00: sid=13 devtype=SBT_TAPE
channel ch00: VERITAS NetBackup for Oracle - Release 5.1 (2002111220)

allocated channel: ch01
channel ch01: sid=14 devtype=SBT_TAPE
channel ch01: VERITAS NetBackup for Oracle - Release 5.1 (2002111220)

Starting restore at 2005-07-28:10:36:08

channel ch00: starting datafile backupset restore
channel ch00: specifying datafile(s) to restore from backup set
restoring datafile 00001 to D:\ORACLE\ORADATA\LSA\SYSTEM01.DBF
restoring datafile 00002 to D:\ORACLE\ORADATA\LSA\UNDOTBS01.DBF
restoring datafile 00006 to D:\ORACLE\ORADATA\LSA\USERS01.DBF
restoring datafile 00008 to D:\ORACLE\ORADATA\LSA\LSA_LINC_MEMBER01.DBF
channel ch01: starting datafile backupset restore
channel ch01: specifying datafile(s) to restore from backup set
restoring datafile 00003 to D:\ORACLE\ORADATA\LSA\DRSYS01.DBF
restoring datafile 00004 to D:\ORACLE\ORADATA\LSA\INDX01.DBF
restoring datafile 00005 to D:\ORACLE\ORADATA\LSA\TOOLS01.DBF
restoring datafile 00007 to D:\ORACLE\ORADATA\LSA\MEMBHISTORY01.DBF
channel ch00: restored backup piece 1
piece handle=bk_u0ogqla80_s24_p1_t564832512 tag=TAG20050728T095512 params=NULL
channel ch00: restore complete
channel ch01: restored backup piece 1
piece handle=bk_u0pgqla80_s25_p1_t564832512 tag=TAG20050728T095512 params=NULL
channel ch01: restore complete
Finished restore at 2005-07-28:13:25:41

Starting recover at 2005-07-28:13:25:41

starting media recovery
media recovery complete

Finished recover at 2005-07-28:13:25:43

sql statement: alter database open

released channel: ch00

released channel: ch01

RMAN>

Recovery Manager complete.
#

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Re: Restore time 15x backup time [message #130374 is a reply to message #130369]

Fri, 29 July 2005 10:54

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

You are using tapes.
You can see most of time is spent during restoration from tapes.
So look into media manager performance (may be something is wrong when files are decompressed from tapes)
and
You are using only 2 channels. May be you can increase it.
and and i assume you have set backup_tape_io_slaves=true. did you also set a larger value for LARGE_POOL_SIZE?

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Re: Restore time 15x backup time [message #130390 is a reply to message #130363]

Fri, 29 July 2005 13:08

Slow Poke
Messages: 7
Registered: July 2004

Junior Member

Yes, I am only using two channels. However, I only have two tape drives. Am I wrong in my understanding that you cannot have more channels than tape units?
I do not have backup_disk_io_slaves set to true. I can do this. My LARGE_POOL_SIZE is 8388608. Should I change this and if so what should it be? I've seen one place that indicated it should be 18MB if I use the default(256KB) channel parameter BLKSIZE.

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Re: Restore time 15x backup time [message #130431 is a reply to message #130390]

Sat, 30 July 2005 04:48

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

>>Am I wrong in my understanding that you cannot have more channels than tape units?
You can have a minumum of two channels per device.
Overallocating the channels may not help.

Regarding the parameters, documentation has very clear account on it.
There is relationship between LARGE_POOL_SIZE,DBWR_IO_SLAVES and BACKUP_TAPE_IO_SLAVES.
a proper setting will help to avoid SGA contention.

http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96566/rcmtunin.htm#449408

and the BLKSIZE or TAPE_IO_SIZE can be increased with RMAN means inside the script.

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Re: Restore time 15x backup time [message #130637 is a reply to message #130363]

Mon, 01 August 2005 13:07

Slow Poke
Messages: 7
Registered: July 2004

Junior Member

I had the BACKUP_TAPE_IO_SLAVES set to true and set the LARGE_POOL_SIZE to 18MB. I also changed the NET_BUFFER_SZ in NetBackup to 128K from 64K. The restore time for a full restore went from about 2hours 45 minutes to about 8 minutes! I couldn't believe the difference. Next we will try it on the production database to ensure that it also works. This also fixed another problem we had with a point-in-time restore/recovery never finishing. Thanks for the help.

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Re: Restore time 15x backup time [message #130638 is a reply to message #130637]

Mon, 01 August 2005 13:20

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

cool~

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