16 February 2023
- Last edited 16 February 2023
Yes, you can add another drive to a RAID5 array.
This is done with the migration feature. It is found in Background Tasks in the Promise Utility. It can also be done from the CLI.
If you are using macOS then there are some issues. Disk Utility won't expand the filesystem beyond the original size of the disk/LUN. If you uncrease the size of LUN, disk utility won't expand the filesystem to use that extra space. There are ways to do this from the CLI, we have a KB on it, take a look and decide if this is something you want to try.
In this case you won't do the rebuilding, but the steps to make macOS use the extra space are the same.
One more point is that a migration can take a long time to complete.
If you have no data it would be much faster and simpler to delete the existing array and create a new one with the extra drive.