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1. Check Primary Database Files Naming Structure
For creating standby database, It’s not important whether primary database files are stored on ASM, ACFS, Filesystem or NFS, because Dbvisit does support all storage methods certified by Oracle. What matters is the naming structure on your primary database - whether it’s OMF (Oracle Managed Files) or whether you use non-OMF (user custom naming). There are several database files for which we need to perform this check:
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this SQL is designed for 19c, it might not work for older Oracle releases. In that case, check manually |
1.1 Using Exclusively OMF Naming Structure
If the previous SQL returned only “OMF” values in Result column for all lines, you’re using OMF naming structure only.
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Otherwise functionality of Dbvisit standby is very limited. If for example OMF datafiles are spread across more diskgroups, you will have to manually create your standby database and the only functionality available will be failover and archivelog synchronization.
1.2 Using Exclusively non-OMF Naming Structure
If the previous SQL returned only “NOT OMF” values in Result column for all lines, you’re using user defined naming structure. The file names contain “human readable” names, for example:
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OMF parameters db_create_file_dest, db_create_online_log_dest_[x] must not be set on primary database nor on standby |
1.3 Using mix of OMF and non-OMF Naming Structure
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If only Controlfiles have different naming structure, it doesn’t matter. Consider your configuration as either 5.1 Exclusively OMF or 5.2 Exclusively non-OMF |
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All of your OMF datafiles and tempfiles mustbe in the same ASM diskgroup / Filesystem directory which is defined by parameter db_create_file_dest AND All of your OMF redo logs mustbe in locations specified by parameter(s) db_create_online_log_dest_[x]. If db_create_online_log_dest_[x] is not set, redo logs must be in locations defined by parameter db_create_file_dest and db_recovery_file_dest (if set) |
2. Determine Standby Files Placement
The information listed below will dictate which parameters you will need to set when running the create standby database process and we will also clarify where the standby database will be created on standby server.
If you’re not using OMF files structure, of if you’re using OMF and non-OMF mix, we recommend to prepare standby file directories on standby server in advance.
2.1 OMF files
Location of OMF files on standby server is completely driven by OMF parameters db_create_file_dest , db_create_online_log_dest_[x] and db_recovery_file_dest. You may change it to place your files on different ASM diskgroup, different filesystem mountpoint etc … OMF parameters on primary and standby are needed even if you don’t make any type of name/path conversion.
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Following rules will apply for different types of files when standby database is created:
2.1.1 Location of OMF datafiles and tempfiles on standby
They will be created on standby in location <db_create_file_dest>/<db_unique_name>/datafile. For example if you have OMF datafile on primary (primary db_unique_name=SOLO):
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db_unique_name is converted by oracle to uppercase for filesystem location. |
2.1.2 Location of OMF redo logs on standby
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Redo member paths on standby will be changed only during standby database activation or graceful switchover |
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If your primary database uses exclusively OMF files, make sure that db_file_name_convert and log_file_name_convert parameters are not set at all when you create standby database |
2.1.3 Primary ASM to Standby filesystem conversion example with OMF files
Let’s have a look how primary ASM to Standby Filesystem conversion works for exclusively OMF primary database.
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Redo member locations will still point to ASM with primary db_unique_name on standby database. This is expected, the paths will be changed only during activation or graceful switchover |
2.2 Non-OMF files
If you have identical filesystem structure on standby and on primary (no path conversion done):
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They contain pair or pairs of strings which are used for path conversion when standby database is created
They are valid on standby database only. On primary, they are not effective.
For Dbvisit to work properly, they need always set on primary and standby (their values are reversed)
2.2.1 Primary filesystem to Standby filesystem conversion example with non-OMF files
Primary database has following configuration:
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Oracle doesn’t use in any way db_unique_name for non-OMF standby database files names. If you would like to create standby database with different db_unique_name you need to provide full path in the convert parameters. For example if we would choose db_unique_name = DBVONEDR for our standby database, we should set:
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2.3 Mixing OMF and Non-OMF files
This configuration is very complex for standby database creation and placement of database files on standby.
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You will need to set OMF parameters when creating standby database to intended locations
You will need to set
db_file_name_convertandlog_file_name_convertas well
2.3.1 Primary filesystem to Standby filesystem path conversion example with OMF and non-OMF mix:
Primary database has following configuration:
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