Bug#840248: debian-installer: Add btrfs subvolume setting for snapshot
package: debian-installer
severity: wishlist
It's enhancement proposal, not bug report. Now Debian system cannot use
whole btrfs power, but we can improve it.
debian-installer can format disk with btrfs now, but it is NOT appropriate
setting with btrfs. We can just format partion with btrfs but cannot create
btrfs "subvolume" at that time.
Subvolume is a bit special idea, you can slice one btrfs partion to some
subvolume and can set quota for each subvolume, also mount directory and
get snapshot for each.
So, I'll propose debian-installer to add btrfs subvolume setting menu or
add subvolume setting like SUSE by default.
For detail, see Btrfs Wiki page
https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-subvolume
Well, for exapmle, openSUSE's installer (YaST2?) creates defalut partition
as btrfs and below subvolumes by default.
------------------------------------------------------------------------------
@/boot/grub2/i386-pc
@/boot/grub2/x86_64-efi
@/home
@/opt
@/tmp
@/usr/local
@/var/crash
@/var/lib/libvirt/images (option "no copy on write")
@/var/lib/mailman
@/var/lib/mariadb (option "no copy on write")
@/var/lib/mysql (option "no copy on write")
@/var/lib/named
@/var/lib/pgsql (option "no copy on write")
@/var/log
@/var/opt
@/var/spool
@/var/tmp
and default / subvolume.
------------------------------------------------------------------------------
- Snapshotting is targeted to default / subvolume and whole system except
above subvolumes. Separating some directories are very important for btrfs
snapshot. It makes easy to rollback to previous snapshot image without any
losing data.
- And, "no copy on write" mount option is important for DB systems
for performance.
- I'm not sure why they separate /boot/grub2/i386-pc and x86_64-efi
If it is hard to add creating subvolume menu, just follow SUSE's decision
is worse.
Some people says "btrfs is not stable", but SUSE and Oracle support it as
commercial support. Some features like RAID5,6 is not stable as it says(*),
but upstream developer Chris Mason says "Aging" state in Facebook(*). So
it's worse to treat btrfs as sane choice and release its power as possible,
IMO.
*) https://btrfs.wiki.kernel.org/index.php/Status
*) https://youtu.be/W3QRWUfBua8?t=17m51s
--
Regards,
Hideki Yamane henrich @ debian.or.jp/org
http://wiki.debian.org/HidekiYamane
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