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Am 12.05.2014 16:30, schrieb Marc Joliet: |
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> In a presentation by Donny Berkholz at Fosdem this year [0], he |
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> mentioned the distro CoreOS, and that they can do atomic updates. I |
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> haven't looked it up in detail, but they're website says that they |
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> use a dual-root scheme where the update is performed in a second |
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> root, which is made the real root after rebooting or after a kexec |
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> [1]. It seems to me that this could be made simpler and easier with |
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> btrfs snapshots. |
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Yes. I will maybe look into your link sometimes ... |
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What I want to research: |
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systemd is now able to "detect" / and /home (and swap) via the GPT-IDs |
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... I wonder if I could get rid of fstab or at least the entries for / |
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Right now when I test my rollbacks I edit (a) the subvolid in the |
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kernel-line of grub.cfg and (b) in /etc/fstab on the "target" subvol. |
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Maybe the second part is redundant, I don't know? |
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I think of generating something like a daily "last known good rootfs" |
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and a related entry in grub2 :-) |
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Just playing here so far, but interesting options. |
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(2nd thought: the subvol would then need to get that GPT-ID?) |
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>> Would mixing hdds and the ssd into one pool make sense? I think, no |
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>> ... ? |
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> |
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> I suspect something like bcache would work (except I remember reading |
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> that btrfs does not work with it yet). |
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So far I run one btrfs on a partition (/dev/sdc3) of an SSD (containing |
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my active /, /home and some data I want to have mounted with speedy |
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performance) and a second btrfs on a 1TB-HDD. |
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I decided to degrade my mdadm RAID1 and dedicate one of the hdds (sdd) |
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completely to btrfs ... then migrated the old LVs into subvols today. |
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Looking good so far (right now I have no more active LVs here ...). |
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Next steps: |
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* see if things work :-) |
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* migrate my other, faster and bigger SSD to the new and shiny root-fs. |
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I boot from the EFI partition there ... but root and stuff is on the 2nd |
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SSD. |
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* decide if to get rid of the old Win7-partition (on sdb) that wasn't |
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booted for years (?) now ... if I don't do that I don't have a second |
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hdd with the same size for mirroring the btrfs ... |
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a) sdd = sdb |
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b) size of sdd > (size of sdb minus partition-win7) |
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So more to consider here. |
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But the btrfs contains mostly pics and music and test-vms ... all backed |
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up via amanda to tape nearly daily, so no specific need for mirroring. |
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> I'm glad I motivated some people to try btrfs themselves :) . |
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Thanks for the reminder .. it fits into my cleaning up here ;-) |
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Now for some scrubbing, backups and watching TV in the meantime. |
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Greets, Stefan |
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