On 26/01/18 09:22, steve-ALUG@hst.me.uk wrote:
Hoping to have a go at this this afternoon. Would appreciate any comments :-)
Well, I dove in...
I let the install of 64 bit *buntu progress. It seems it went BIOS mode. I have two disks. I got part way into the install process, let the machine set up partitions the way it wanted to, wrote them to disk, then quit the install. I then used a live CD to set up both disks with the same partition layout. (I'm setting up RAID 1 - mirroring)
I used
sfdisk -d /dev/sda > part_table
edited part_table, removed all uuids, changed sda to sdb then
sfdisk /dev/sdb < part_table
& voilà - identical sized (unformatted) partitions.
I then rebooted and restarted the installation process, and did manual partitioning. I deleted each partition in turn, and recreated it, marking it as part of a raid array. Deleting and recreating using the maximum available space meant basically that the partitions ended up exactly the same size as before deleting, but of the right type (raid member).
I wrote changes to disk, then did manage/create raid level 1, 2 active devices, 0 spares. I matched up a partition on each disk.
I raided md0 biosgrub "boot" partition (NB this is not the "/boot" partition/directory md1 / partition md2 /home partition & some swap partitions.
I then proceeded with the install. I then hit the problem.
The disks, being >2TB won't work well with a traditional partition table, so the installer chose a GPT partition table. Fair enough. BUT you can't make the "biosgrub" partition part of a raid array, or at least as far as I could tell as the installation failed with a grub error. Something like
grub-install: warning: this GPT partition label contains no BIOS Boot Partition; embedding won't be possible. embedding is not possible, but this is required for RAID
I've had to delete md0 and reformat these as normal fat32 partitions flagged as "biosgrub". Apparently you can easily use grub-install to install the relevant files to the "backup" partition.
This seems like a bit of a GOTCHA to me. You might RAID everything on the disks so one disk failure means you can still continue, except if you haven't remembered to set up the backup biosgrub partition.
So I can: a) Live with it. b) Switch to UEFI mode. I gather the install process is different, though I've not tried it. Does this have similar gotchas? c) Use built in "hardware raid" that my new machine is supplied with. Everything I've read says Linux's raid is better, because of the recovery tools that are available in case a drive fails.
I'm currently going with a). If that's mad, I haven't gone far enough into customising to not want to back out and start again.
Any comments and/or experience, again, gladly accepted.
Cheers Steve