#3594 Specify Raid drives by their ID/path rather than by /dev/sdX
I already filed a similar issue to the smart supervision: It would be nice, if Webmin would specifiy components of raid volumes by their unique ID or by their device path instead of their device files (such as /dev/sda).
I created a raid10 volume using Webmin and specified the first four scsi-devices (/dev/sda, /dev/sdb, /dev/sdc and /dev/sdd). The creation worked fine, Webmin created the raid and I also was able to create a filesystem and mount it.
But then I powered down the PC, connected an external USB device and then rebooted. Because udev manages device files dynamically, the USB disk now received /dev/sdc and the original raid components /dev/sdc and /dev/sdd shifted to /dev/sdd and /dev/sde.
Since Webmin created the /etc/mdadm.conf using the device files (/dev/sda ... /dev/sdd), mdadm could not reassemble the raid after reboot, so I had to adjust /etc/mdadm.conf manually.
Wouldn't it be much better to address device files by their /dev/disk/by-id/ and/or /dev/disk/by-path/ links provided by many linux distributions?
Best regards
That could certainly be done..
What would the mdadm.conf file contain in this case though? Should the UUID= option be used in the ARRAY line, or should device files just use their /dev/disk/by-uuid paths?
For the moment, I think, that it should be sufficient, to replace the /dev/sdX-references in the DEVICE=... line and in the ARRAY=...devices=... line by their representatives in the /dev/disk/by-xyz directory.
What I did, is to replace all /dev/sdX references by the /dev/disk/by-path/pci-0000:xxx files in the mdadm.conf. In case of a raid, I think it is useful to use the /dev/disk/by-path/ entries instead of the "by-uuid" ones. In case of a drive failure, one would replace the defective drive by a new one (at the same channel) and start a rebuild. This would cause the ID (or uuid) to change while the path remains constant. What do you think about the idea to let the user select the type of reference in the GUI ("direct file" (/dev/sdX), "by-id", "by-path" or "by-uuid")? (The same might be applied for the smart monitoring.)