How to Add Diskgroup in ASM |
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- čas přidán 21. 07. 2024
- In this episode of daily DBA, I pick up 6 important #DBA related questions and give my answers! Do not forget to checkout BONUS QUESTION at the end of the video!
00:00 Intro
01:50 If we perform a switchover operation in real time. How will we have to manage the connection string for end users? since after switchover standby will act as a primary database. Do we have to modify connection string for all the user at client side? or is there any other thing which is need to be done?
07:45 How to add the disk group in ASM and how to tell the steps in interview ?
10:29 How can I reduce the gap between primary and standby Database?
17:27 What are all the monitoring tools used by DBAs now and before?
21:14 Is there any query to get list of tables that should be reorganized? I have a problem in free space in the FS and I need to reduce the datafiles size?
22:12 We have 2 node RAC setup and when I try to connect via connection string, I get "connection lost" error. When I try to connect again, the connection succeeds. What could be the issue?
Bonus Question
24:58 What is the meaning of “migration” in “Oracle (database) migration”?
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After watching the way you answer questions in this program, I have no reason not to subscribe. You are a genius! If you could start adding subtitles as you speak, then you will be a DBA beast.
Great presentation for all of us.
Thanks for answering my doubt.
Thanks for the videos..
Thanks for choosed my question and it's very helpful to me...thank you soo much
most welcome!
Nice sir. its good helpful for us
Thank you sir very helpful for us
Hello Arun, what if we forgot to mention the fail_group name while creating a diskgroup with normal or high redundancy. I know in this case every disk in a diskgroup is its own fail group disk ..But I am not clear if any disk fails then what happened?
for the dataguard gap ....
wouldn't it be easier to enable the FAL_CLIENT and FAL_SERVER Parameters that will ship the missing archivelog directly on standby ! the only step is to restore the missing archivelog from backup on the primary server if there are no longer present on the primary
You are 100% right, but this can only be used when new archive generation is relatively slow and standby can come in sync.
If you primary is having heavy archive generation and even if you try to restore archives, ship and apply, the primary has 1000s of new archives. You end up in same place! You resolve 1000 archive gap, meanwhile primary generates 1000 more archives!
I used DPA, a solarwinds product for db monitoring..
Awesome job please keep continuing. Question: Oracle DB has OMF. someone deleted all the control files. OS -Oracle Linux 7, DB 12c and OS already restarted. Archive log mode is not enabled. Without using the RMAN how to recover the database?
Good one, picked it up for upcoming episode!
How flashback works for multitenant architecture? Like if I have 2 pdbs named HR and Sales inside a single CDB and I am performing any change/ release in either of pdb and due to some failure I need to revert changes to original state, before changes. How will it work?
Good question, picked it up for upcoming episodes. Will answer it soon!
We need to knw what is general guideline for sizing db_block_size and db_multi_block_read
for an application that does many full table scans?
This will be a tedious task coz you need to know average row length and then go for DB BLOCK SIZE.
How to dismount diskgroup without stopping database
Hi Arun,
can you explain how 3 scan IPs resolve a 8 node rac in Oracle . because we 8 node in the cluster and only 3 scan IPs. how is it possibly resolve these 8 nodes. Can you tell us.
Sure, picked up your question for upcoming episodes!
I loved these videos!! thanks for sharing. I have more questions.. sorry about it
1.Do we need to take separate license for Real time apply.
2. If there is only 2 or 3 archivelog gap is there and when we copy the logs into standby will it automatically apply? or do we need to register the logs in standby? (I tried 2 times like incremental backup.)
3.If the database size is like 20TB or more is it ok to use enterprise manager? my doubt is enterprise manager keep checking in regular intervals like 10sec or 30sec will it impact any performance? and loading that much huge data?
1. Not required
2. Not required to register it manually if MRP is running. If you copy archives and plan to recover standby using RMAN, then you will have to first register archives and then recover the DB. Later you can start MRP.
3. OEM is a monitoring tool, it does not load 20 TB (in your case) into OEM! It only monitors that status / performance / issues for you DB/Host/storage.
@@dbagenesis Thank you
1:43 : I did
when you demo it?
Hi Arun,
What's the difference between row chaining and row migration?
Good question, I have picked it up for the next episode!
Hi how do I migrate from oracle to postgresql and from oracle to aws rds?
You can use Ora2pg free tool for migration from Oracle to Postgre sql.
For later, you can always use export & import.
How can we export and import LOB datatype table?
My table size near about in TB.
if you have facing any problem with expdp the use exp/imp. It is tested by me.
You can use the SYSCS_UTIL.SYSCS_IMPORT_TABLE and SYSCS_UTIL.SYSCS_IMPORT_DATA procedures to import data into a table that contains a LOB column.
You can use the SYSCS_UTIL.SYSCS_EXPORT_TABLE and SYSCS_UTIL.SYSCS_EXPORT_QUERY procedures to write LOB data, along with rest of the column data, to a single export file.
Does OEM have separate license for basic use if all the targets are separately licensed?
OEM Cloud Control is free as long as you have at least ONE Oracle product under support you want to monitor with Cloud Control.
For further information, Please review the link below:
docs.oracle.com/cd/E73210_01/OEMLI/OEMLI.pdf
@@dbagenesis Thank you very much!
Hi ,
I have one request to you ...
Can you please focus on OEM.(Oracle Enterprise Manager)
Please create some video regarding installing and monitoring by OEM...
Noted, rather I have plan to announce an online training for OEM. Currently my team is doing a POC to see if we can give 3 servers to each student during the training so that server 1 acts as OEM server and other 2 acts as targets.
Once POC is done, will be announcing it soon!
How do we know when to rebuild index and what are the ways to monitor index?
??
You get an idea of the current state of the index by using the ANALYZE INDEX VALIDATE STRUCTURE command.
SQL> ANALYZE INDEX IDX_GAM_ACCT VALIDATE STRUCTURE;
There are two rules of thumb to help determine if the index needs to be rebuilt:
1. If the index has height greater than four, rebuild the index.
2. The deleted leaf rows should be less than 20%.
One more question from me...
What is the difference btw AWR,AHHD,ASH reports ?
how to explain the AWR report for interview purpose ?
Good one, picked it up for next episode! will be answering it shortly!
Appdynamics tool for monitoring db, servers & the overall application
How to migrate mysql to oracle online?
You can use Oracle SQL Developer tool to perform the migration. Google it up "MySQL to Oracle Migration using SQL Developer" and you should get your answers!
Hi Arun,
Thanks for these daily sessions, my question is what is the method to perform a switch over if both primary and standby are on RAC, I had done the switch over on RAC and ran into issues as other instances were not done with the role change and crossed the down time😂
Thanks
Ajaz
Hahaaaa, I have been there and know how it feels when you screw up switchover!
Do you have specific details of what was the error / issue?
Generally, 97% of switchovers fail due to wrong configuration of LOG_ARCHIVE_DEST_2 parameter.
1% switchovers fail due to no configuration of SRL!
In case of RAC Data guard Broker(DGMGRL) utility is best way ....
At first configure DGMGRL in database side ,mention LOG_ARCHIVE_DEST_2 parameter properly ...
Check and validate configuration.....
After that when it's required just fire 1 singel line command...
Switch over will be done properly and db role will change automatically..
@@dbagenesis
Hi Arun,
There was no error ad switch over was successful but only on the node where I was connected, later I checked the status of all the nodes which were not in open or mount modes, I want to know what precautionary measures need to take while doing switch over if your both primary and standby are on RAC.
Thanks
Ajaz
what is row chaining, how does it happen? How can you we reduce it? How do you we
correct it?
Good one, picked it up for upcoming episode !! Will answer in soon!
Thanks!😊
Solarwinds and HP OMI
Sir I wanted to learn online oracle DBA training so any possible please
You can find all of our courses via below link
dbagenesis.com/courses