====== SnapRAID - Disks - Replace a data disk in an existing array ======

If the data disk is lost, see the **recovering section** in the manual.

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====== Copy all files to the new disk ======

Copy all the files to the new disk, maintaining the same directory structure and names.

<code bash>
cp -av /from_dir/. /to_dir
</code>

<WRAP important>
**WARNING:**  Some other mechanisms to copy the files, such as **rsync** may be problematic, especially if using older versions of these alternative commands.

  * Older versions are not able to copy the sub-second timestamps.

</WRAP>

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====== Change the SnapRAID configuration ======

Change the SnapRAID configuration to point the disk at the new mount point and run a "diff" command to ensure that everything is placed correctly.

<code bash>
snapraid diff
</code>

<WRAP info>
**NOTE:**  If **"diff"** reports some "added" or "removed" files, it is likely the files have been copied with a different directory structure.

  * In such case, fix it, until "diff" reports only "equal", "restored" or "copied" files.

</WRAP>

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====== Check that the files were really copied correctly ======

Run a **"check"** audit command limited to the replaced disk to check the check-sum of all the files.

<code bash>
snapraid check -a -d DISK_NAME
</code>

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====== Update the SnapRAID state ======

Run **"sync"** to update the SnapRAID state.

  * This command will be almost immediate.

<code bash>
snapraid sync
</code>

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