Duplicate Database - Performance Question

Is the number of channels used to duplicate a database (using RMAN) dependent on the number of channels used to create the backupset?
Example: 200Gb database (10g), 2 channels used during hot level zero daily backups, all files to be used for duplication still on disk. To increase the speed of a duplication, should I increase the number of channels used in creating my hot level zero database backup? Or is there some RMAN command I can add to my run block that will increase the speed of the 200Gb duplication effort?
The scenarion is that I have many databases to duplicate in as short of a time as possible. The larger databases take several hours each and I am trying to find a way to make this happen quicker.
Thank you.

you're not dependent on the number of channels you used for the backup in your scenario. If anything you need to balance how fast your disk can feed vs. the number of channels you want to use. I have had good performance with 4 channels with a disk based duplication coming from a simple jbod nfs mount - anything beyond that made performance worse in my situation. You might be able to get more channels from mount fed by a SAN (I was able to use 8 channels) but then you will need to consider the i/o load of your host as well. If you had mentioned tape well then that would be a discussion you would need to have with your storage admin as some solutions limit the number of concurrent reads from the tape library.

Similar Messages

Duplicate target database related questions

I have several questions regarding duplicate database and please help me in understanding this process. I really appreciate it.
1) When I look through log file of duplicate command it looks like the control file be created twice. One is after the restore and the other one is after recover. Am I right and why?
2) What exactly this command "switch clone datafile all;" do?
3) How to bring the other node into cluster db after clone from a single instance to one of the node in a cluster?
Thank you very much for your help!!
Shirley

1) When I look through log file of duplicate command it looks like the control file be created twice. One is after the restore and the other one is after recover. Am I right and why?Creates only once. Control file creation after recovery does not make sense to me. You will have to recover again if your controlfile is recreated
What exactly this command "switch clone datafile all;" This is like saying "Dear controlfile, please recreate it by changing all your source datafile locations to the newones mentioned in the duplicate database". For most practical scenarios, you will use DB_FILE_NAME_CONVERT that will map source database file locations to the new file locations for the duplicate database.
How to bring the other node into cluster db after clone from a single instance to one of the node in a cluster?Just use a "single instance to RAC conversion" method. Once a duplicate database is created it can be used like any other database.
Message was edited by:
Srinivas.R

Question: Will online backup impact database performance for DB6 V9.1

Dear All,
I would like to know will online backup impact the database performance? for eg: access will be slower if online backup is currently running. Appreciate if someone can shed some light on this as i'm new to DB6.
I know for oracle it will impact due the performance due to tablespace are locked in backup mode and this will increaes I/O load due to every block is written to redo log during backup instead of just the changes.
Hope to hear from you soon.
Cheers,
Nicholas Chang.

Hello Nicholas,
Here is some additional information on throttling utilities such as online backups:
SET UTIL_IMPACT_PRIORITY command
Changes the impact setting for a running utility. Using this command, you can:
throttle a utility that was invoked in unthrottled mode
unthrottle a throttled utility (disable throttling)
reprioritize a throttled utility (useful if running multiple simultaneous throttled utilities)
Scope
Authorization
One of the following:
sysadm
sysctrl
sysmaint
Required connection
Instance. If there is more than one partition on the local machine, the attachment should be made to the correct partition. For example, suppose there are two partitions and a LIST UTILITIES command resulted in the following output:
ID = 2
Type = BACKUP
Database Name = IWZ
Partition Number = 1
Description = online db
Start Time = 07/19/2007 17:32:09.622395
State = Executing
Invocation Type = User
Throttling:
Priority = Unthrottled
Progress Monitoring:
Estimated Percentage Complete = 10
Total Work = 97867649689 bytes
Completed Work = 10124388481 bytes The instance attachment must be made to partition 1 in order to issue a SET UTIL_IMPACT_PRIORITY command against the utility with ID 2. To do this, set DB2NODE=1 in the environment and then issue the instance attachment command.
Command syntax
>>-SET UTIL_IMPACT_PRIORITY FORutility-idTOpriority----><
Command parameters
utility-id
ID of the utility whose impact setting will be updated. IDs of running utilities can be obtained with the LIST UTILITIES command.
TO priority
Specifies an instance-level limit on the impact associated with running a utility. A value of 100 represents the highest priority and 1 represents the lowest priority. Setting priority to 0 will force a throttled utility to continue unthrottled. Setting priority to a non-zero value will force an unthrottled utility to continue in throttled mode.
Examples
The following example unthrottles the utility with ID 2.
SET UTIL_IMPACT_PRIORITY FOR 2 TO 0
The following example throttles the utility with ID 3 to priority 10. If the priority was 0 before the change then a previously unthrottled utility is now throttled. If the utility was previously throttled (priority had been set to a value greater than zero), then the utility has been reprioritized.
SET UTIL_IMPACT_PRIORITY FOR 3 TO 10
Relationship between UTIL_IMPACT_LIM and UTIL_IMPACT_PRIORITY settings
The database manager configuration parameter util_impact_lim sets the limit on the impact throttled utilities can have on the overall workload of the machine. 0-99 is a throttled percentage, 100 is no throttling.
The SET UTIL_IMPACT_PRIORITY command sets the priority that a particular utility has over the resources available to throttled utilities as defined by the util_impact_lim configuration parameter. (0 = unthrottled)
Using the backup utility as an example, if the util_impact_lim=10, all utilities can have no more than a 10% average impact upon the total workload as judged by the throttling algorithm. Using two throttled utilities as an example:
Backup with util_inpact_priority 70
Runstats with util_impact_priority 50
Both utilities combined should have no more than a 10% average impact on the total workload, and the utility with the higher priority will get more of the available workload resources. For both the backup and runstats operations, it is also possible to declare the impact priority within the command line of that utility. If you do not issue the SET UTIL_IMPACT_PRIORITY command, the utility will run unthrottled (irrespective of the setting of util_impact_lim).
To view the current priority setting for the utilities that are running, you can use the LIST UTILITIES command.
Usage notes
Throttling requires that an impact policy be defined by setting the util_impact_lim configuration parameter.
Regards,
Adam Wilson
SAP Development Support

Error while duplicate database for standby

Hello Guys,
Both of my database are 10gR2 and Linux is the operating system.
I am trying to create a standby database for my production database.
I have matched the directory structure of primary and standby database and there is no conflict. Directory permissions are also set.
After taking the rman backup from production database when i connect auxiliary database from production. I run this command to duplicate database and create standby database.
rman
set until sequence XXXX;
duplicate target database for standby dorecover nofilenamecheck;
I get this error:
executing Memory Script
executing command: SET until clause
Starting restore at 04-JUN-11
using channel ORA_AUX_DISK_1
channel ORA_AUX_DISK_1: starting datafile backupset restore
channel ORA_AUX_DISK_1: restoring control file
channel ORA_AUX_DISK_1: reading from backup piece /tmp/backup_files/standby_control_1jme2far_1_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 06/04/2011 21:00:37
RMAN-03015: error occurred in stored script Memory Script
ORA-19870: error reading backup piece /tmp/backup_files/standby_control_1jme2far_1_1
ORA-01565: error in identifying file '/u01/app/oracle/product/10.2.0/db_1/dbs/spfileORCL.ora'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
*/tmp/backup_files/standby_control_1jme2far_1_1 file exists*
* spfileORCL.ora* exists on both servers in same directory and same path.
Can you please suggest where is the problem?
Thank you so much.
Imran

ORA-19870: error reading backup piece /tmp/backup_files/standby_control_1jme2far_1_1
ORA-01565: error in identifying file '/u01/app/oracle/product/10.2.0/db_1/dbs/spfileORCL.ora'
ORA-27037: unable to obtain file statusLinux-x86_64 Error: 2: No such file or directory
Might the backup piece not exist or file is unae to read at this time. Can you check is this physically exist Or not?
And preferred to take new fresh backup and perform duplicate

Duplicate database in 11g

Hi all,
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 02/17/2010 09:18:42
RMAN-03015: error occurred in stored script Memory Script
RMAN-06172: no AUTOBACKUP found or specified handle is not a valid copy or piece
I have got stuck with this error, while iam trying to duplicate database using rman from active database clause, I have checked in backup location for target and the autobackups are still available.
thanks in advance.

Handle:      user12984527
Status Level:      Newbie
Registered:      Apr 15, 2010
Total Posts:      72
Total Questions:      28 (25 unresolved)
so many questions & so few answers,
when all else fails, Read The Fine Manuals
http://download.oracle.com/docs/cd/B19306_01/backup.102/b14191/rcmbackp.htm#BRADV143

Oracle 11 G database performance tuning

How to indexing the oracle 11G database?
Thanks in advance.

Your question is like if you ask "Tell me how to fix a car". As you know people spend years learning how to fix different problems with cars; the same applies to database performance tuning. There is no way to answer this question in one post. Please ask a more specific question in an apropriate (database related) forum.
cheers

Database Performance Checks

Oracle : 10.2.0.3
OS : Linux 64 bit
Issue : Slow performance at 11-30PM complained by client.
Checks done :
1. Ran AWR between 11 PM and 12 Noon.
CPUs : 4 SGA Size : 2,000M (100%) Buffer Cache : 1,584M (79.2%) Shared Pool 1,129M (56.4%)
ADDM suggest SGA_TARGET to increase from 2000MB to 2500MB.
2. top 5 events
Top 5 Timed Events                                         Avg %Total
~~~~~~~~~~~~~~~~~~                                        wait   Call
Event                                 Waits    Time (s)   (ms)   Time Wait Class
db file scattered read            1,952,811       4,804      2   30.5   User I/O
CPU time                                          3,448          21.9
db file sequential read             149,712       1,921     13   12.2   User I/O
read by other session               293,022         877      3    5.6   User I/O
log file sync                         9,920         157     16    1.0     Commit
          -------------------------------------------------------------       3. Stats are upto date.
4. Index rebuild requirement is not there
SQL> SELECT name,height,lf_rows,del_lf_rows,(del_lf_rows/lf_rows)*100 as ratio FROM INDEX_STATS;
no rows selected5. Average 100 sessions will connect to the database
6. Checked all logs fr any disconnection details
7. Application is running from weblogic
Questions : How to certify the performance is good or slow from the above observations. I am able to feel the statistics are the similar for the different periods where I ran AWR report.
: Other than the user as a DBA what are the other checks can be done to monitor the performance

It's difficult to use AWR or Statspack to "certify" database performance is good. It just depends what "performance is good" means.
Most of the time it's application response time which is the right metric: database response time is only a part of application response time and AWR/Statspack cannot easily link database response time and application response time.
[11.2 Concepts Guide Principles of Application Design and Tuning| http://download.oracle.com/docs/cd/E11882_01/server.112/e10713/cncptdev.htm#CHDEHHIJ] says
>
Define clear performance goals and keep historical records of metrics
An important facet of development is determining exactly how the application is expected to perform and scale. For example, you should use metrics that include expected user load, transactions per second, acceptable response times, and so on. Good practice dictates that you maintain historical records of performance metrics. In this way, you can monitor performance proactively and reactively (see "Performance Diagnostics and Tuning").

Database performance issue (8.1.7.0)

Hi,
We are having tablespace "payin" in our database (8.1.7.0) .
This tablespace is the main Tablespace of our database which is dictionary managed and heavily accessed by the user SQL statements.
Now we are facing the database performance issue during the peak time (i.e. at the month end) when no. of users use to run the no. of large reports.
We have also increased the SGA sufficiently on the basis of RAM size.
This tablespace is heavily accessed for the reports.
Now my question is,
Is this performance issue is because the tablespace is "dictionary managed" instead of locally managed ?
because when i monitor the different sessions through OEM, the no. of hard parses is more for the connected users.
Actually the hard parses should be less.
In oracle 8.1.7.0 Can we convert dictionary managed tablespace to locally managed tablespace ?
by doing so will the problem will get somewhat resolve ? will it reduce the overhead on the dictionary tables and on the shared memory ?
If yes then how what is procedure to convert the tablespace from dictionary to locally managed ?
With Regards

If your end users are just running reports against this tablespace, I don't think that the tablespace management (LM/DM) matters here. You should be concerned more about the TEMP tablespace (for heavy sort operations) and your shared pool size (as you have seen hard parses go up).
As already stated, get statspack running and also try tracing user sessions with wait events. Might give you more clues.

New HP EVA6000 SAN and now bad database performance problems

Hello,
we changed our SAN Hardware to a HP EVA6000 and moved all Data to there.
It is intended that storagesystem is for all Servers (File/Print, Exchange, Oracle Databases and MSSQL Databases).
According to the best practice papers of HP we created one big discgroup (fata harddiscs) and created virtual discs for our servers.
After doing this the database performance was terrible bad!
Especially the multiple random IO is absolutely worse.
As a first countermeasure we created a second discgroup on faster harddiscs and moved the database contents to there. We analyzed the IO and moved several database file to different virtual discs.
The performance is better now, but still not like the 4 year old SAN System!
Of course we questioned HP and even let them do a performance analysis but up to now we have no solution... The performance analysis report will be available on thursday.
Does anybody had the same experience or how did you configure the Database and EVA SAN to work with an appropiate performance?

Hi,
I'm not an Oracle person, but do work with EVA SAN's.
Your 48 FATA disk, disk group is capable of 4800 I/O operations per second [48 x 100] but the disks are only rated for 30% duty cycle and spin at 7200 rpm.
The 16 FC drive Disk Group I/O operations rating depends on the speed the disks spin at. 10K rpm disks are rated at 130 I/O per sec [2080 for the group] and if they are 15K rpm disks then 170 I/O per sec [2720 for the group]. Both are rated for 100% duty cycle.
I seem to recall having have read somewhere that Oracle prefers to have it's logs on separate storage to it's data.
If your shelves had the spare disk slots I would put in 72 GB 15K rpm disks up to the capacity required {+ overhead } + head room for reasonably predictable growth over the anticpated life of the equipment.
Here is a link to the HP Best Practice guide for EVA 4/6/8000's
http://h71028.www7.hp.com/ERC/downloads/4AA0-2787ENW.pdf
I hope this helps you understand the storage that you are working with a bit better. The old saying of "more heads make for better performance" is still true, however budget can have some affect in performance. ;-)
Jim

Oracle database performance after server reboot

hi masters,
this is not some kind of question, but a discussion. some statements come from our client that after weekly reboot of system, the oracle database performance is low for some time and increase after some time(say 2 days).
i think it is but obvious, because at reboot oracle flushes all cache, and temporary space, so it need to re parse the sql statements and perform some disc I/O's so it might need some time and hence performance will degrade.
but at the same time some people claim that after reboot their database performance is better than their normal performance for some days. it seems controversial that's why i am posting it here.
what might be the reason behind this?? prior can have a valid reason of hard parsing, but what with second case??
any clarification is highly appreciated...
thank you
regadrs
VD

Vikrant,
You should wait for some time buddy, its weekend ;-) .
this is not some kind of question, but a discussion. some statements come from our client that after weekly reboot of system, the oracle database performance is low for some time and increase after some time(say 2 days).i think it is but obvious, because at reboot oracle flushes all cache, and temporary space, so it need to re parse the sql statements and perform some disc I/O's so it might need some time and hence performance will degrade.
>
I would start from saying that checking the performance when the system just started, is a wrong approach. There would be lots of IOs , parsing, calculations(related to memory allocations) happening so there would be a delay/bad performance at that time. Very simple example can be parsing, another can be memory allocation. Oracle doesn't allocate the entire memory in the instance startup that is allocated to the memory areas but allocates just the bare minimum that is needed to start the instance and than after the startup, it keeps on allocating the memory. So surely enough, with the startup and after a while of it, there would be a different performance than that after the instance hsa already been started and the workload informations have started coming up.
Its correct that Oracle would deallocate all the caches with the reboot as the instance is on the memory(physical) and with the reboot , that would be flushed including the SGA which is allocated over it. Temporary tablespace is now not freed with the reboot. I guess its a rather illogical thing to do but that's what is there now. Oracle keeps the segment allocated even after the reboot is issued, hence the reason for larger temporary tablespaces.
>
but at the same time some people claim that after reboot their database performance is better than their normal performance for some days. it seems controversial that's why i am posting it here.
what might be the reason behind this?? prior can have a valid reason of hard parsing, but what with second case??
>
This should not come as a surprise once we understand what might be happening with this process. Assume a situation where you have undersized caches. For example, shared pool . which is very heavily used for database , if this is going to be undersized and you are not using automatic memory management, you won't be enjoying the dynamic management of this parameter. Now, if you do lots of parsing , thanks to your wrongly written queries, you would eventually end up filling up shared pool to its max thus leaving no space for incoming new hard parsed cursors. Here , if you can't manage to add more memory to add to it, the only solution left would be to flush the shared pool( as good as rebooting the db because this would do the same) and than make space for the new cursors. The performance is going to be better becausethe cursors would not be getting flushed out immediately and will be kept in the shared pool as long as its not filled up again.Once you have reached to limit of it, again there would be performance benefit. So there are always odds added to the statements like this that I rebuilt my index , I got better, I rebooted my server, my querie are much faster now. Most of the time when these kind of statements are given, they are based on what we have seen, without understading what actually might have happened. So I would siggest to hear the statement but not take them as a rule of thumb to follow.
Hope this all makes some sense for you and would help somewhat.
Aman....

How about a separate forum Database-Performance

hi friends/Moderators,
I had one thing to give feedback/suggestion to give , but didnt know of any link/place to put it.
So opening a new thread over it.
I see many new threads related to Database Performance, sql tuning, redo/undo ( and many other architecture related things which can impact the performance of the database).
How about a idea of having another forum Database-Performance like we have Database-General now?
Personally I would like to start replying to performance related questions so that apart from helping the OPs i learn more about performance issues which other people see or face outside of my workplace.
What do you guys say?
Cheers!

Kunwar wrote:
hi friends/Moderators,
I had one thing to give feedback/suggestion to give , but didnt know of any link/place to put it.
So opening a new thread over it.For such questions, please post them over the Community Discussions forum.
I see many new threads related to Database Performance, sql tuning, redo/undo ( and many other architecture related things which can impact the performance of the database).
How about a idea of having another forum Database-Performance like we have Database-General now?
Personally I would like to start replying to performance related questions so that apart from helping the OPs i learn more about performance issues which other people see or face outside of my workplace.
What do you guys say?
This was asked by me in 2008. Please have a read of the thread,
Can We Have a Perfomance Tuning Forum?
That said, it may break things even more. Don't take it personally but just take the example of this question. You are here from some time now and even then, you wrongly posted this question in a product forum even when there is already a non-technical, community feedback forum is in place. So may be people won't use a separate forum of Performance and will keep on posting the questions in different forums, just like what happens now too. And with every new forum added, the overhead would also increase (my guess) .
And another thing that comes to mind is that since the forums are already scheduled for a major upgrade in the mid-April , I doubt that such request would be fulfilled , at least right now because last time, when the upgrade of the forums happened, it wasn't a smooth one and the focus of the OTN team would be surely to make sure that the history won't repeat itself.
Just my 2 cents.
Aman....

Oracle Database Performance With Semantic

Hello,
Is there a Developer's Guide for Semantic that specifically talks about database performance with the Semantic network/tables/indexes? We are having issues with performance the larger the semantic network becomes.
Any help or pointers would be appriciated.
Thanks
-MichaelB

Matt,
Thanks for your response. Here are the answers to the questions about our setup/environment.
1) Are you querying multiple models and/or a model + entailment? If so, are you using a virtual model and using the ALLOW_DUP=T query option?
A single model, no entailments. We attempted to use multiple models, and a virtual model (with ALLOW_DUP=T), however the UNION ALL in the explain plan made the query duration unacceptable.
2) Are you using named graphs?
No named graphs.
3) How many triples are you querying?
Approximately 85 million.
4) What semantic network and/or datatype indexes have been created?
We have PCSGM, PSCGM, PSCM, PCSM, CPSM, and SCM.
5) What is your hardware setup (number and type of disks, RAM, processor, etc.)?
We are running the 11.2.0.3 database on a Sun Solaris T2000, we have ASM managing our disks from RAID5, I believe currently we have two Disk Groups with the indexes in one and the data tables in the other. We have 32 GB of memory, and 32 CPUs. However, it is not the only thing running on the machine.
6) How much memory have you allocated to the database (pga, sga, memory_target, etc.)?
We have the memory_target set to 9GB, the db_cache_size set to 2GB, and the db_keep_cache_size set to 4.5GB. `pga_aggregate_target` is set to 0 (auto), as is `sga_target`.
(Since my initial request, we pinned the RDF_VALUE$ (~2.5GB) and C_PK_VID (~1.7GB) objects in the KEEP buffer cache, which drastically improved performance)
7) Are you using parallel query execution?
Yes, some of the more complex queries we run with the parallel hint set to 8.
8) Have you tried dynamic sampling?
Yes. We have ODS set to 3 for our more complex queries, we have not altered this much to see if there is a performance gained by changing this value.
Thanks again,
-Michael

Database performing Very slow - Lots of wait events

My database is on Oracle10g on Sun 5.10
The users are complaining about database is very slow.
I analyzed the indexes & later on rebuild them, hardly it has only 5% performance improvement.
http://i812.photobucket.com/albums/zz43/sadeel00/untitled1.jpg
http://i812.photobucket.com/albums/zz43/sadeel00/untitled2.jpg
ADDM has no recommendations.

Duplicate post - Database performing Very slow - Lots of wait events
Srini

Duplicate database synchronize

I have duplicated the database “prod” to “dup”.
$rman target sys/oracle@ORIGDB auxiliary /
RMAN> duplicate target database to DUP nofilenamecheck;
My question is in order to synchronize the duplicate database from time to time, do I need to drop the duplicate database first and then re-run the “RMAN> duplicate target database to DUP;” command?

You don't have to drop the database first.
Shutdown and then start in nomount before you run the duplicate command.

Duplicate database issue

Dear all,
When the target database is in use(many users are connect to the database), is it can do the duplicate database action?

srp wrote:
You need to copy only the backups from Host A to Host B under the same directory structure where you had taken the backups on Host A if not, you can catalog the backups on Host B.
No need to copy the archives from host A to host B. Hope your doubt is clarified :)Hi,
If i does not copy the the archives from host A to host B,how can i do the recovery. when duplicate database ,there will be raise the error.
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 02/07/2012 07:24:02
RMAN-03015: error occurred in stored script Memory Script
RMAN-06053: unable to perform media recovery because of missing log
RMAN-06025: no backup of log thread 1 seq 35 lowscn 1482261 found to restore

Duplicate Database - Performance Question

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