Multipath disks

In case your hardware consists of multipath disks, some extra steps are required to make it work with croit.

We highly advise against using multipath disks with Ceph. Ceph already offers high availability and load balancing. Multipath disks in fact hinder Ceph when it comes to high availability.

If you still want to use multipath disks, you first need to enable support in croit, then reboot your servers.

1. Make sure you're running a croit version that supports DM multipathing. This feature is supported in croit starting with v2411.0.
2. Make sure that your server image also supports multipathing. Likewise, images since v2411.0 support it.
3. In the croit UI, navigate to Croit in the bottom left.
4. Click Add and search for croit enable dm multipath support. Enable it and click on Save.
5. Now reboot your servers.
6. Navigate to Servers > Disks. The disks should now show with device paths of the form /dev/mapper/.... You may have left-over disks (of the individual paths) from before the reboot, clean them up by selecting them (they are marked in red) and clicking Forget.
7. You can enable additional columns on the Disks page to show multipath information.

Croit offers a template to edit the multipath.conf file on your servers. To edit it:

1. Navigate to Config > Templates.
2. Search for the template named multipath-conf.
3. Make your changes and save them. Please note that the (rendered) contents of this template are accessible without authentication. Don't put any sensitive information in it.
4. Reboot your servers. The template is only applied after a reboot.
5. Navigate to Servers > Disks and verify that your disks are still correctly detected and multipathed.