---
title: "assess migration reference"
url: "https://docs.yugabyte.com/stable/yugabyte-voyager/reference/assess-migration/"
---

# assess migration reference

YugabyteDB Voyager assess migration reference

yb-voyager assess-migration

The following page describes the following assess commands:

- [assess migration](#assess-migration "assess migration")
- [assess migration bulk](#assess-migration-bulk "assess migration bulk")

## assess migration

[Assess the migration](/stable/yugabyte-voyager/migrate/assess-migration "Assess the migration") from source (PostgreSQL, Oracle) database to YugabyteDB.

### Syntax

```text
Usage: yb-voyager assess-migration [ <arguments> ... ]
```

### Arguments

The valid *arguments* for assess migration are described in the following table:

CLI flag

Config file parameter Description 

--assessment-metadata-dir

```yaml
assess-migration:
  assessment-metadata-dir:
```

Directory path where assessment metadata like source database metadata and statistics are stored. Optional flag, if not provided, it will be assumed to be present at default path inside the export directory. 

--iops-capture-interval

```yaml
assess-migration:
  iops-capture-interval:
```

Interval (in seconds) at which Voyager will gather IOPS metadata from the source database for the given schema(s).  
Default: 120 

--target-db-version

```yaml
assess-migration:
  target-db-version:
```

Specifies the target version of YugabyteDB in the format `A.B.C.D`.  
Default: latest stable version 

--oracle-db-sid

```yaml
source:
  oracle-db-sid:
```

Oracle System Identifier you can use while exporting data from Oracle instances. Oracle migrations only. 

--oracle-home

```yaml
source:
  oracle-home:
```

Path to set `$ORACLE_HOME` environment variable. `tnsnames.ora` is found in `$ORACLE_HOME/network/admin`. Oracle migrations only. 

[--oracle-tns-alias](/stable/yugabyte-voyager/reference/yb-voyager-cli/#oracle-options "--oracle-tns-alias")

```yaml
source:
  oracle-tns-alias:
```

TNS (Transparent Network Substrate) alias configured to establish a secure connection with the server. Oracle migrations only. 

--send-diagnostics

```yaml
send-diagnostics:
```

Enable or disable sending [diagnostics](/stable/yugabyte-voyager/reference/diagnostics-report/ "diagnostics") information to Yugabyte.  
Default: true  
Accepted parameters: true, false, yes, no, 0, 1 

--source-db-host

```yaml
source:
  db-host:
```

Domain name or IP address of the machine on which the source database server is running.  
Default: localhost 

--source-db-name

```yaml
source:
  db-name:
```

Source database name. 

--source-db-password

```yaml
source:
  db-password:
```

Password to connect to the source database. If you don't provide a password via the CLI during any migration phase, yb-voyager will prompt you at runtime for a password. Alternatively, you can also specify the password by setting the environment variable `SOURCE_DB_PASSWORD`. If the password contains special characters that are interpreted by the shell (for example, # and $), enclose it in single quotes. 

--source-db-port

```yaml
source:
  db-port:
```

Source database server port number.  
Default: PostgreSQL (5432), Oracle (1521) 

--source-db-schema

```yaml
source:
  db-schema:
```

Source schema name(s) to export. In case of PostgreSQL, it can be single or a comma-separated list of schemas: `schema1,schema2,schema3`. 

--source-db-type

```yaml
source:
  db-type:
```

Source database type (postgresql, oracle). 

--source-db-user

```yaml
source:
  db-user:
```

Username of the source database. 

[--source-ssl-cert](/stable/yugabyte-voyager/reference/yb-voyager-cli/#ssl-connectivity "--source-ssl-cert")

```yaml
source:
  ssl-cert:
```

Path to a file containing the certificate which is part of the SSL `<cert,key>` pair. 

[--source-ssl-crl](/stable/yugabyte-voyager/reference/yb-voyager-cli/#ssl-connectivity "--source-ssl-crl")

```yaml
source:
  ssl-crl:
```

Path of the file containing source SSL Root Certificate Revocation List (CRL). 

[--source-ssl-key](/stable/yugabyte-voyager/reference/yb-voyager-cli/#ssl-connectivity "--source-ssl-key")

```yaml
source:
  ssl-key:
```

Path to a file containing the key which is part of the SSL `<cert,key>` pair. 

[--source-ssl-mode](/stable/yugabyte-voyager/reference/yb-voyager-cli/#ssl-connectivity "--source-ssl-mode")

```yaml
source:
  ssl-mode:
```

One of `disable`, `allow`, `prefer`(default), `require`, `verify-ca`, or `verify-full`. 

[--source-ssl-root-cert](/stable/yugabyte-voyager/reference/yb-voyager-cli/#ssl-connectivity "--source-ssl-root-cert")

```yaml
source:
  ssl-root-cert:
```

Path of the file containing source SSL Root Certificate. 

--primary-only

```yaml
source:
      primary-only:
```

Skip read replica discovery and assessment, and assess only the primary database. PostgreSQL migrations only.  
Default: false 

--source-read-replica-endpoints

```yaml
source:
      read-replica-endpoints:
```

Comma-separated list of read replica endpoints. PostgreSQL migrations only.  
Format endpoints as `host:port`.  
For example, `host1:5432, host2:5433`.  
Default port: 5432 

-e, --export-dir

```yaml
export-dir:
```

Path to the export directory. This directory is a workspace used to store exported schema DDL files, export data files, migration state, and a log file. 

-l, --log-level

```yaml
log-level:
```

Log level for yb-voyager.  
Accepted values: trace, debug, info, warn, error, fatal, panic  
Default: info 

--log-max-size-mb

```yaml
log-max-size-mb:
```

Maximum size in MB of a yb-voyager log file before it is rotated. Also applies to the Debezium log file during live migration.  
Default: 200 

--log-max-backups

```yaml
log-max-backups:
```

Maximum number of rotated log files to retain. Older files are deleted. Use -1 to retain all rotated log files.  
Default: 10 

--start-clean — Cleans up the project directory for schema or data files depending on the export command.  
Default: false  
Accepted parameters: true, false, yes, no, 0, 1. 

-h, --help — Command line help. 

-y, --yes — Answer yes to all prompts during the export schema operation.  
Default: false  
Accepted parameters: true, false, yes, no, 0, 1 

-c, --config-file — Path to a [configuration file](/stable/yugabyte-voyager/reference/configuration-file "configuration file"). 

--run-guardrails-checks

```yaml
assess-migration:
  run-guardrails-checks:
```

Run guardrails checks during migration.  
Default: true  
Accepted values: true, false, yes, no, 0, 1  
**Note**: Setting this flag to false is unsafe, as it skips critical pre-migration validations (such as source/target database permissions, binary dependencies, and version compatibility) and may lead to migration failures or data issues. Leave the default (true) unless you have a specific reason to disable checks.

### Example

Configuration file:

```sh
yb-voyager assess-migration --config-file <path-to-config-file>
```

CLI:

```sh
yb-voyager assess-migration --source-db-type postgresql \
        --source-db-host hostname --source-db-user username \
        --source-db-password password --source-db-name dbname \
        --source-db-schema schema1,schema2 --export-dir /path/to/export/dir
```

## assess migration bulk

[Assess the migration](/stable/yugabyte-voyager/migrate/assess-migration "Assess the migration") from multiple source (Oracle) database schemas to YugabyteDB.

### Syntax

```text
Usage: yb-voyager assess-migration-bulk [ <arguments> ... ]
```

### Arguments

The valid *arguments* for assess migration bulk are described in the following table:

Argument

Description/valid options 

--bulk-assessment-dir Directory path where assessment data is output. 

--continue-on-error Print the error message to the console and continue to next schema assessment.  
Default: true.  
Accepted parameters: true, false, yes, no, 0, 1. 

--fleet-config-file Path to the CSV file with connection parameters for schema(s) to be assessed. The first line must be a header row.  
Fields (case-insensitive): 'source-db-type', 'source-db-host', 'source-db-port', 'source-db-name', 'oracle-db-sid', 'oracle-tns-alias', 'source-db-user', 'source-db-password', 'source-db-schema'.  
Mandatory: 'source-db-type', 'source-db-user', 'source-db-schema', and one of \['source-db-name', 'oracle-db-sid', 'oracle-tns-alias']. 

-h, --help Command line help. 

--send-diagnostics Enable or disable sending [diagnostics](/stable/yugabyte-voyager/reference/diagnostics-report/ "diagnostics") information to Yugabyte.  
Default: true  
Accepted parameters: true, false, yes, no, 0, 1 

--start-clean Cleans up the project directory for schema or data files depending on the export command.  
Default: false  
Accepted parameters: true, false, yes, no, 0, 1. 

-y, --yes Assume answer to all prompts during migration.  
Default: false 

-l, --log-level Log level for yb-voyager.  
Accepted values: trace, debug, info, warn, error, fatal, panic  
Default: info 

--log-max-size-mb Maximum size in MB of a yb-voyager log file before it is rotated. Also applies to the Debezium log file during live migration.  
Default: 200 

--log-max-backups Maximum number of rotated log files to retain. Older files are deleted. Use -1 to retain all rotated log files.  
Default: 10

### Example

```sh
yb-voyager assess-migration-bulk \
    --fleet-config-file /path/to/fleet_config_file.csv \
    --bulk-assessment-dir /path/to/bulk-assessment-dir \
    --continue-on-error true \
    --start-clean true
```

The following is an example fleet configuration file.

```text
source-db-type,source-db-host,source-db-port,source-db-name,oracle-db-sid,oracle-tns-alias,source-db-user,source-db-password,source-db-schema
oracle,example-host1,1521,ORCL,,,admin,password,schema1
oracle,example-host2,1521,,ORCL_SID,,admin,password,schema2
oracle,,,,,tns_alias,oracle_user,password,schema3
```