On 28 January 2018 at 17:40, steve-ALUG@hst.me.uk wrote:
So the options are: Non-raided partition to boot from, rest raided. (Bios or UEFI mode) Extra disk to boot from, non raided. Raid the other. Either way, I have a single point of failure and I have to mitigate it somehow.
Booting from an array created by mdadm is certainly possible and should avoid the SPOF issue.
It's been a while since I've done it; where I'm using software RAID it tends to be just for storage and I have a separate boot drive simply because there's nothing of substance on it, so when it fails I use it as an excuse to rebuild. Desktop machines where the O/S partition contains stuff I don't want to lose are backed up but not RAIDed so I've not needed to boot from software RAID for a couple of years.
For Ubuntu* I found the following which looks like it covers configuring RAID at installation time: https://help.ubuntu.com/community/Installation/SoftwareRAID
If you have a desktop kicking around with something like VirtualBox installed you can of-course play with this in a virtual machine before messing around with real hardware. I recall it being a bit tricky only because it was outside my knowledge but actually fairly straightforward otherwise.
*Other distros are available, of-course.