Hah! Sorry, I didn't know I need to prove it
I use
btrbk
(with
snapshot_create onchange
option) to make incremental backups of my btrfs subvolumes to external harddisks, and since I use a separate subvolume for
/var
I thought the root partition should not see any changes except for systemupdates or configuration changes. This was a wrong assumption, and showing the difference between my snapshots, I can see most changes come down to
/etc/cups/subscriptions.conf
and
/etc/cups/subscriptions.conf.0
For example:
Code: Select all
# btrfs send --no-data -p /.btrfs_root_hdd/@ssd_backups/@.20210802T070001+0200 /.btrfs_root_hdd/@ssd_backups/@.20210802T080001+0200 | btrfs receive --dump
At subvol /.btrfs_root_hdd/@ssd_backups/@.20210802T080001+0200
snapshot ./@.20210802T080001+0200 uuid=71c7c6c1-7f7c-7b41-aa34-05c962aba2c6 transid=138110 parent_uuid=f46565e2-2601-474a-abfb-7bd2b9ee4ee1 parent_transid=137824
utimes ./@.20210802T080001+0200/ atime=2021-07-31T22:25:11+0200 mtime=2021-08-02T07:34:01+0200 ctime=2021-08-02T07:34:01+0200
utimes ./@.20210802T080001+0200/tmp atime=2021-07-03T15:00:06+0200 mtime=2021-08-02T07:37:46+0200 ctime=2021-08-02T07:38:02+0200
utimes ./@.20210802T080001+0200/etc/cups atime=2021-07-18T12:46:41+0200 mtime=2021-08-02T07:32:15+0200 ctime=2021-08-02T07:34:01+0200
unlink ./@.20210802T080001+0200/etc/cups/subscriptions.conf.O
utimes ./@.20210802T080001+0200/etc/cups atime=2021-07-18T12:46:41+0200 mtime=2021-08-02T07:32:15+0200 ctime=2021-08-02T07:34:01+0200
link ./@.20210802T080001+0200/etc/cups/subscriptions.conf.O dest=etc/cups/subscriptions.conf
unlink ./@.20210802T080001+0200/etc/cups/subscriptions.conf
utimes ./@.20210802T080001+0200/etc/cups atime=2021-07-18T12:46:41+0200 mtime=2021-08-02T07:32:15+0200 ctime=2021-08-02T07:34:01+0200
utimes ./@.20210802T080001+0200/etc/cups atime=2021-07-18T12:46:41+0200 mtime=2021-08-02T07:32:15+0200 ctime=2021-08-02T07:34:01+0200
utimes ./@.20210802T080001+0200/etc/cups/subscriptions.conf.O atime=2021-08-02T06:33:55+0200 mtime=2021-08-02T06:33:55+0200 ctime=2021-08-02T07:34:01+0200
mkfile ./@.20210802T080001+0200/o510606-138084-0
rename ./@.20210802T080001+0200/o510606-138084-0 dest=./@.20210802T080001+0200/etc/cups/subscriptions.conf
utimes ./@.20210802T080001+0200/etc/cups atime=2021-07-18T12:46:41+0200 mtime=2021-08-02T07:32:15+0200 ctime=2021-08-02T07:34:01+0200
update_extent ./@.20210802T080001+0200/etc/cups/subscriptions.conf offset=0 len=1531
chown ./@.20210802T080001+0200/etc/cups/subscriptions.conf gid=7 uid=0
chmod ./@.20210802T080001+0200/etc/cups/subscriptions.conf mode=640
utimes ./@.20210802T080001+0200/etc/cups/subscriptions.conf atime=2021-08-02T07:32:15+0200 mtime=2021-08-02T07:32:15+0200 ctime=2021-08-02T07:34:01+0200
The contents of
/etc/cups/subscriptions.conf
(at the moment) are:
Code: Select all
# Subscription configuration file for CUPS v2.3.1
# Written by cupsd
NextSubscriptionId 86
<Subscription 74>
Events printer-state-changed printer-restarted printer-shutdown printer-stopped printer-added printer-deleted job-state-changed job-created job-completed job-stopped
Owner username
Recipient dbus://
LeaseDuration 3600
Interval 0
ExpirationTime 1627885904
NextEventId 6
</Subscription>
<Subscription 78>
Events printer-state-changed printer-restarted printer-shutdown printer-stopped printer-added printer-deleted printer-modified
Owner username
LeaseDuration 86400
Interval 0
ExpirationTime 1627914802
NextEventId 4
</Subscription>
<Subscription 79>
Events printer-state-changed printer-restarted printer-shutdown printer-stopped printer-added printer-deleted printer-modified job-state-changed job-created job-completed job-stopped job-progress
Owner username
LeaseDuration 86400
Interval 0
ExpirationTime 1627914813
NextEventId 2
</Subscription>
<Subscription 80>
Events printer-changed
Owner root
LeaseDuration 86400
Interval 60
ExpirationTime 1627915031
NextEventId 1
</Subscription>
<Subscription 81>
Events all
Owner anonymous
Recipient dbus://
LeaseDuration 86400
Interval 0
ExpirationTime 1627915031
NextEventId 5
</Subscription>
<Subscription 84>
Events printer-changed
Owner root
LeaseDuration 86400
Interval 60
ExpirationTime 1627941600
NextEventId 1
</Subscription>
<Subscription 85>
Events all
Owner anonymous
Recipient dbus://
LeaseDuration 86400
Interval 0
ExpirationTime 1627941600
NextEventId 1
</Subscription>
By "Inspecting the files" you mean comparing the contents what is changing? In this example between today 08:00 shown above and an hour earlier, at 07:00 line 10 was this: