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Asked: 2016-04-28 19:23:35 +0800 CST

How to use snapshots with BTRFS in Ubuntu along with a separate HOME partition

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My goal is to make snapshots while upgrading software. I installed Ubuntu primary partitions and Using MBR with Legacy BIOS with a separate HOME partition in another HDD formatted in XFS and root in *"/" in BTRFS

I know there's this package called apt-btrfs-snapshot.

This my system layout :

$lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 223.6G  0 disk 
├─sda1   8:1    0 215.6G  0 part /
└─sda2   8:2    0     8G  0 part [SWAP]
sdb      8:16   0 465.8G  0 disk 
└─sdb1   8:17   0 465.8G  0 part /home

Note:

I have to get back to BTRFS when I reinstall . I've been using Ext4

encryption

1 Answers

  1. from your screenshot of the disks tool i can see that you are trying to create an lvm physical volume using the extended partition (/dev/sda1), you can't do this because an extended partition is only a container for other partitions, in this case your btrfs (/dev/sda5) and swap partitions (/dev/sda6), but not in an lvm compatible way. This is also the reason why lvmdiskscan cannot see it.

    The simplest solution would be to , after backing up the data, use the partition with the BTRFS filesystem as your lvm physical volume then create a logical volume within it to restore the data to, assuming it wasn't too full. The command you were trying to run would then be 

    sudo pvcreate /dev/sda5

    A better choice would be to repartition the SSD (ideally with a GPT instead of MS-DOS partition table, then you can make many many partitions without the limitations of older hardware requiring extended partitions) to not use the extended partition at all. This is not essential given that you are using LVM which allows you to ignore those limitations because of its abstractions. Don't repartition if you need to preserve an existing OS.

    FYI, btrfs is optimised for lots of small files like a mail server , its not the most efficient filesystem for a home dir. ext4 might be a better choice as its more general performer

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