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Standby FAQ's - Version 8.0

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Description

Below are some of the Frequently Asked Questions by customers , while installing the new standby version 8.0, which is quite different from the previous versions of standby , with loads of improvements and features being made available in the new version. The commands have also changed in version 8.0, so its always a Best Practice to view the version specific user guide to avoid issues.

FAQ's

 

  1. The Dbvisit Standby v7 requires a database schema/user to store Dbvisit repository data. The Dbvisit Standby v8 does not need it. Can we drop the Dbvisit repository database user after an upgrade to v8?
  2. In the Dbvisit Standby GUI is an Active Task List. Are only jobs started from the GUI reported there? For example - the scheduled jobs from primary and standby to transfer and apply the archived logs do not show up there in the Active Task List. 
  3. The documentation states that we can run a “dbvisit daemon” on my primary and standby. Can you explain what the purpose and benefit is to run the “dbvisit daemon” on both standby and primary?
  4. How do you apply license for my standby version 8.0?
  5. What are the new Dbvisit standby v8 features? 
  6. What are considerations to be taken into an account when setting up a schedule for DBvisit Standby?
  7. Are there any bandwidth requirements between primary and secondary site?
  8. Does the Dbvisit synchronize the archive log or redo log to DR site DB server?
  9. Can archivelogs be applied while the standby database is in read only mode?
  10. Is ARCHSOURCE and ARCHDEST the same as Oracle Archive Log Destination?
  11. Is compression be enabled by default?
  12. Is email notification enabled by default?
  13. Do you recommend implementing AMM for both Primary and Standby?
  14. What Network Encryption algorithm does dbvnet use?
  15. How does licensing work?
  16. Is running the FORCE LOGGING option recommended for Primary database?
  17. How do I log a ticket to Dbvisit Support?
  18. How do I create a support package?
  19. Does Dbvisit work with Oracle enterprise edition?
  20. Can we use Oracle Enterprise edition as primary and Oracle Standard edition for Standby?
  21. If we are using Multitenant Container database can we add a PDB to existing CDB and does Dbvisit Standby creates the PDB in the standby?
  22. What if one node goes down in RAC instance does Dbvisit still sends the archivelogs to standby?
  23. Is it necessary to install Dbvserver on a separate machine?
  24. Can we have Primary database as on-premise and standby in cloud?
  25. Can I have two standby databases for a single primary database.
  26. Can we restrict the access of user in central console to certain actions?
  27. Advantages of using Dbvnet over SSH

 

1. The Dbvisit Standby v7 requires a database schema/user to store Dbvisit repository data. The Dbvisit Standby v8 does not need it. Can we drop the Dbvisit repository database user after an upgrade to v8?

Standby V8 uses an external data store for its repository therefore after you have upgraded to Standby V8 you can drop the Oracle repository owner from the database (ie. dbvisit7). See Link for additional Information.

https://dbvisit.atlassian.net/wiki/display/DS8QSG/Installing+Dbvisit+Standby#InstallingDbvisitStandby-3.1.TheDbvisitStandbyRepositoryOverview

 

2. Inside the dbvserver web GUI we can see the ACTIVE TASK LIST. Is it intentional that only those jobs are reported there, which have been started from the web GUI? The scheduled jobs from primary and standby to transfer and apply the archived logs do not show up there in our setup.?

Please see the below link for additional information on this topic.

https://dbvisit.atlassian. net/wiki/display/DS8QSG/Centra l+Console%3A+Tasks+and+Task+Tr acking

 

3. The documentation states that we can run a “dbvisit daemon” on my primary and standby. But we do not get for what purpose. The management GUI runs on a third and separate machine and archivelog transfer and apply are scheduled jobs on the primary and standby server. Can you explain what the purpose and benefit is to run the “dbvisit daemon” on both standby and primary?

The shipment & apply logs can either be scheduled as they were in Standby V7.  Optionally you can ship / apply them via a background/daemon process instead of the scheduled process.You would choose one or the other not both. See linked page for additional information

https://dbvisit.atlassian.net/ wiki/display/DS8QSG/Dbvisit+St andby+Scheduling#DbvisitStandb yScheduling-4.RunningDbvisitSt andbyintheBackground

 

4. How to Apply License for my standby version 8.0 

The steps to apply license for the standby version 8.0 is provided in the link below. The standby 8.0 has completely different command sets compared to the previous versions, so its best always to refer the user guide.

https://dbvisit.atlassian.net/wiki/display/DS8QSG/Dbvisit+Standby+License

 

5. What are the unique features of the standby product ? 

NEW Dbvisit Standby Version 8 Features: 

  • New Central Console - easily manage one or multiple configurations from one web based interface
  • Support for Cascading Standby Database (Create standby from Standby)
  • New Dbvnet network component - enhanced encryption and compression
  • New Oracle RAC support with the option to create a RAC enabled Standby Database.

http://www.dbvisit.com/products/dbvisit_standby_database_for_oracle_disaster_recovery/

 

6. How is the RPO and RTO while deploy Dbvisit Standby ?

When scheduling Dbvisit Standby there are a few key factors to consider

such as the Recovery Time Objective (RTO) and Recovery Point Objective (RPO) of your environment. This is a business decision, but certain factors play a key role.

These are:

  • Speed of the network
  • Activity on the database
  • Speed of the disks
  • Compression method chosen and CPU power to compress and uncompress archive log files.

 The schedules can be customized based on requirements. There is continuous monitoring which can set up to get notified for any delay. The daemon process automatically detects the archivelog in the primary and forces a logswitch in primary when it does not see a new archivelog for a certain period, by doing this it makes sure that the delay between Primary and Standby are minimum.

 

7. What is the required bandwidth between primary and secondary site, how to estimate?

To estimate the bandwidth, we might need to understand from the database perspective

  • Size of the redologs.
  • Number of archivelogs generated in a day and size.
  • What is the application environment (OLTP/DWH)?

We should also test network speed under these circumstances.

 

8. Does the Dbvisit synchronize the archive log or redo log to DR site DB server? , if its archivelog will there will be a delay ?

Archivelogs are used to synchronise the Standby, there is a legitimate delay in any DR solutions, since the archivelog from the primary must be sent to the Standby site and applied, but this will also be based on the other factors explained in the FAQ-7.

But rest assured in case of any disaster scenarios, activating a standby site is very straight forward and easy process using Dbvisit product and can be done using a single Command Line or by using a GUI interface.

 

9. Can archivelogs still be applied when the Standby Database is in Read Only mode?

When the Standby database is in READ ONLY mode, archived logs can be transferred from Primary to Standby, BUT the archived logs can’t to be applied till the Standby Database is in managed recovery mode.

 

10. Is ARCHSOURCE and ARCHDEST the same as Oracle Archive Log Destination?

No it should never be the same.

ARCHSOURCE and ARCHDEST variables should contain the same directory on primary and standby server. On standby server, this directory is used to receive archivelogs from primary. On primary server, this directory is not used, but when the primary server switches role and becomes standby, then this directory will be used to receive archivelogs from primary database

 

11. Will compression be enabled by default?

Compression is disabled by default.

It can assist with faster network transfer time as fewer data will be transferred between the primary and standby servers.

 

12. Is email notification enabled by default?

E-Mail notification is disabled by default.

If Dbvisit Standby has failed to transfer or apply an archived log after the set threshold has been reached, an email alert will be sent.

 

13. Do you recommend implementing AMM for both Primary and Standby?

By default when creating a new DDC file in version 8, the AMM module is disabled for the primary database.  This is to ensure the Dbvisit AMM module does not interfere with archive log purging options implemented as part of RMAN backup strategies.

It is however recommended to implement AMM on the Standby side to manage the archived logs after they’ve been applied.

 

14. What Network Encryption algorithm does dbvnet use?

From 8.0.18 TLS1.2 and above is used.

 

15.How does licensing work?

Licensing is done per database which is db_name.

In an multitenant environment we consider CDB. The license key is applied based on the primary CDB name.

 

16. Is running the FORCE LOGGING option recommended for Primary and why?

The FORCE LOGGING option is the safest method to ensure all the changes made in the primary database will be captured and available for recovery.

If the number of archives on the primary side is not too big , once you set LOGGING, that signifies a large number of NOLOGGING are being performed on the primary database. The end result is that these operations are not applied to the standby due to no redo information being available for these transactions.

The standby will appear to be up to date, but when these objects are accessed – when standby is open in READ-ONLY mode, roles were changed with the primary or it is activated – you will receive unrecoverable errors.

Our recommendation setting and keeping FORCE LOGGING on primary to protect your standby.

 

17. How do I log a ticket to Dbvisit Support?

https://support.dbvisit.com/hc/en-us/articles/360000362775-How-to-create-a-support-ticket

 

18. How to create a support package?

https://dbvisit.atlassian.net/wiki/spaces/DS8QSG/pages/117932052/Troubleshooting#Troubleshooting-2.Creatingasupportpackage

 

19. Does Dbvisit work with enterprise edition?

Yes, Dbvisit Standby works with enterprise edition, but we strongly recommend to go with Data guard which comes with enterprise edition

 

20. Can we have Enterprise edition as primary and Standard edition for DR and does Dbvisit works with this configuration?

We have done internal testing and the Dbvisit Standby works with above configuration but you have to make sure that you don’t use any enterprise edition features in your primary and moreover it defeats the purpose of having a DR which is not exactly matching your Primary database. So we strongly not recommend doing the above.

 

21. If we are using Multitenant Container database can we add a PDB to existing CDB and does Dbvisit Standby creates the PDB in the standby?

No, The PDB must exist before you create the standby and it cannot create the PDB to standby when you create a new PDB in primary and moreover with Oracle Standard Edition we can create only one PDB.

 

22. What if one node goes down in RAC instance does Dbvisit still sends the archivelogs to standby?

Yes, if you have Installed Dbvisit in shared storage and use VIP for configuring your dbvnet, dbvagent and configured dbvnet and dbvagent as cluster resources. This should automatically fail over the available node and then continue sending archivelogs to the standby. Below are some of the links from documentation which talks about these in detail.

https://dbvisit.atlassian.net/wiki/spaces/DS8QSG/pages/115015757/Advanced+-+Oracle+RAC+Configurations#Advanced-OracleRACConfigurations-3.1.1.ThenewVirtualIP

https://dbvisit.atlassian.net/wiki/spaces/DS8QSG/pages/115015757/Advanced+-+Oracle+RAC+Configurations#Advanced-OracleRACConfigurations-5.Example2:AddDbvnetandDbvagentasClusterResources

If you have installed Dbvisit in local storage on both the servers and still used VIP you have to schedule a job to copy files from active node to another and then manually startup the Dbvisit services in the other node once the node goes down.

 

23. Is it necessary to install Dbvserver in a separate machine?

No, but it is recommend since if you have multiple configurations it would be easier to manage with a single dbvserver installation and manage all the primary and standby pairs. If you have only single configuration and cannot afford to have a separate machine , you could still install the dbvserver in standby machine thereby in case of a true DR scenario the central console GUI is still available and you can use it to activate.

 

24. Can we have Primary database as on-premise and standby in cloud?

Yes, this is possible and the below user guide link talks about this in detail.

https://dbvisit.atlassian.net/wiki/spaces/DS8QSG/pages/165118036/Example+Cloud+Configurations

 

25. Can I have two standby databases for a single primary database.

Yes, this possible as well. You could have below configurations.

  1. Single Primary database sending archivelogs to two standby database.
  2. Creating a standby database from another standby database in different servers (Cascade standby database).
  3. Creating two standby databases from primary database in the same server.

Below link from user guide discusses these configurations in detail.

https://dbvisit.atlassian.net/wiki/spaces/DS8QSG/pages/564625524/Advanced%3A+Creating+two+standby+databases+on+same+server

https://dbvisit.atlassian.net/wiki/spaces/DS8QSG/pages/366739559/Cascading+Standby+Databases+with+Dbvisit+Standby

 

26. Can we restrict the access of user in central console to certain actions?

This is work under progress and the next version should have these features not immediately but eventually. But you could create individual users and provide them their own access instead of using admin user.

 

27. Advantages of using Dbvnet over SSH

1. Uses faster compression than SSH: Up to 4x during compression and 3.5x during decompression

2. More robust than SSH: As Dbvnet has only the featureset required for its own use-case, it does not offer as many potential entrypoints to attackers. For example, Dbvnet does not implement shell access, as it does not need it.

 3. Works on windows, whereas SSH must be installed and set up separately: Configuring SSH is more elaborate than configuring Dbvnet, and also installing SSH can introduce security risks as it allows shell access to the host system.

4. Same level of security due to an equivalent implementation of TLS encryption.

 

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