> # Guidelines and Limitations

> This section explains the database guidelines for this feature.

> For information about CFS merge support, refer to the Cisco MDS 9000 Family NX-OS System Management Configuration Guide for detailed concepts.

> When merging two device alias databases, follow these guidelines:

> - Verify that two device aliases with different names are not mapped to the same pWWN.
> - Verify that two different pWWNs are not mapped to the same device aliases
> - Verify that the combined number of the device aliases in both databases does not exceed 8191 (8K). For example, if database N has 6000 device aliases and database M has 2192 device aliases, this merge operation will fail.

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