# 2026-01-28 proxmox mastodon disk usage alert

## transcript (edited)

root@mastodon ~# df -h
Filesystem                Size      Used Available Use% Mounted on
vpool/subvol-103-disk-3
                         16.0G      9.9G      6.1G  62% /
vpool/subvol-103-disk-1
                        300.0G    271.9G     28.1G  91% /mnt/db
vpool/subvol-103-disk-0
                          1.5T    429.2G      1.0T  29% /mnt/barman
vpool/subvol-103-disk-2
                        100.0G     10.6G     89.4G  11% /mnt/elastic
none                     10.0M      4.0K     10.0M   0% /dev
run                     125.9G      1.9M    125.9G   0% /run
shm                     125.9G     10.1M    125.9G   0% /dev/shm
udev                    125.8G         0    125.8G   0% /dev/fuse
udev                    125.8G         0    125.8G   0% /dev/full
udev                    125.8G         0    125.8G   0% /dev/null
udev                    125.8G         0    125.8G   0% /dev/random
udev                    125.8G         0    125.8G   0% /dev/tty
udev                    125.8G         0    125.8G   0% /dev/urandom
udev                    125.8G         0    125.8G   0% /dev/zero
none                     10.0M      4.0K     10.0M   0% /proc/sys/kernel/random/boot_id

root@mastodon ~# du -hd1 /mnt/db/data
981.0K  /mnt/db/data/global
512     /mnt/db/data/pg_commit_ts
512     /mnt/db/data/pg_tblspc
512     /mnt/db/data/pg_twophase
512     /mnt/db/data/pg_notify
512     /mnt/db/data/pg_serial
7.0M    /mnt/db/data/pg_multixact
512     /mnt/db/data/pg_dynshmem
27.5K   /mnt/db/data/pg_replslot
81.0K   /mnt/db/data/pg_subtrans
10.0K   /mnt/db/data/pg_logical
153.0G  /mnt/db/data/pg_wal
18.5K   /mnt/db/data/pg_stat_tmp
512     /mnt/db/data/pg_snapshots
45.4M   /mnt/db/data/pg_xact
118.8G  /mnt/db/data/base
512     /mnt/db/data/pg_stat
271.8G  /mnt/db/data

root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman list-back
ups db-manual
db-manual 20260118T055415 - F - Sun Jan 18 06:09:23 2026 - Size: 117.4 GiB - WAL Size: 66.7 GiB
db-manual 20260118T034737 - F - Sun Jan 18 04:10:03 2026 - Size: 117.4 GiB - WAL Size: 305.5 MiB
db-manual 20260118T034717 - F - FAILED
db-manual 20260118T034618 - F - FAILED
db-manual 20260118T034232 - F - FAILED
db-manual 20260118T031522 - F - Sun Jan 18 03:35:01 2026 - Size: 117.4 GiB - WAL Size: 104.6 MiB

root@mastodon ~#
set -l backup_ids 20260118T034737 20260118T034717 20260118T034618 20260118T034232 20260118T031522
for backup_id in $backup_ids
    docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman delet
e db-manual $backup_id
end

Deleting backup 20260118T034737 for server db-manual
Deleted backup 20260118T034737 (start time: Wed Jan 28 20:53:00 2026, elapsed time: less than one second)
Deleting backup 20260118T034717 for server db-manual
Deleted backup 20260118T034717 (start time: Wed Jan 28 20:53:02 2026, elapsed time: less than one second)
Deleting backup 20260118T034618 for server db-manual
Deleted backup 20260118T034618 (start time: Wed Jan 28 20:53:03 2026, elapsed time: less than one second)
Deleting backup 20260118T034232 for server db-manual
Deleted backup 20260118T034232 (start time: Wed Jan 28 20:53:04 2026, elapsed time: less than one second)
Deleting backup 20260118T031522 for server db-manual

root@mastodon ~# df -h | grep /mnt
                        300.0G    272.0G     28.0G  91% /mnt/db
                          1.5T    319.0G      1.2T  21% /mnt/barman
                        100.0G     10.6G     89.4G  11% /mnt/elastic
root@mastodon ~# du -hd1 /mnt/db/data/
1.0M    /mnt/db/data/global
512     /mnt/db/data/pg_commit_ts
512     /mnt/db/data/pg_tblspc
512     /mnt/db/data/pg_twophase
512     /mnt/db/data/pg_notify
512     /mnt/db/data/pg_serial
7.0M    /mnt/db/data/pg_multixact
512     /mnt/db/data/pg_dynshmem
27.5K   /mnt/db/data/pg_replslot
81.0K   /mnt/db/data/pg_subtrans
10.0K   /mnt/db/data/pg_logical
153.0G  /mnt/db/data/pg_wal
146.5K  /mnt/db/data/pg_stat_tmp
512     /mnt/db/data/pg_snapshots
45.4M   /mnt/db/data/pg_xact
118.8G  /mnt/db/data/base
512     /mnt/db/data/pg_stat
271.8G  /mnt/db/data/

root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman recei
ve-wal --drop-slot db-manual
Dropping physical replication slot 'barman_secondary' on server 'db-manual'
ERROR: Cannot drop replication slot 'barman_secondary' on server 'db-manual' because it is in use.

root@mastodon ~ [2]# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman statu
s db-manual
Server db-manual:
        Active: True
        Disabled: False
        PostgreSQL version: 14.18
        Cluster state: in production
        Current data size: 118.2 GiB
        PostgreSQL Data directory: /mnt/db/data
        Current WAL segment: 0000000200000DDC000000F4
        Passive node: False
        Retention policies: not enforced
        No. of available backups: 1
        First available backup: 20260118T055415
        Last available backup: 20260118T055415
        Minimum redundancy requirements: satisfied (1/0)

root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman receive-w
al --stop db-manual
Stopped process receive-wal(60000)
root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman receive-w
al --drop-slot db-manual
Dropping physical replication slot 'barman_secondary' on server 'db-manual'
Replication slot 'barman_secondary' dropped

root@mastodon ~# psql -U postgres -p 5432 -c 'SELECT * FROM pg_replication_slots;'
    slot_name     | plugin | slot_type | datoid | database | temporary | active | active_pid | xmin | catalog_xmin |
restart_lsn  | confirmed_flush_lsn | wal_status | safe_wal_size | two_phase
------------------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+-
-------------+---------------------+------------+---------------+-----------
 barman_secondary |        | physical  |        |          | f         | t      |    1425420 |      |              |
DDD/3E000000 |                     | reserved   |               | f
 barman_manual    |        | physical  |        |          | f         | f      |            |      |              |
DB6/8F000000 |                     | extended   |               | f
 barman           |        | physical  |        |          | f         | t      |     138767 |      |              |
DDD/3E000000 |                     | reserved   |               | f
(3 rows)

root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman receive-w
al --stop db-manual
Stopped process receive-wal(66018)
root@mastodon ~# psql -U postgres -p 5432 -c 'SELECT * FROM pg_replication_slots;'
    slot_name     | plugin | slot_type | datoid | database | temporary | active | active_pid | xmin | catalog_xmin |
restart_lsn  | confirmed_flush_lsn | wal_status | safe_wal_size | two_phase
------------------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+-
-------------+---------------------+------------+---------------+-----------
 barman_secondary |        | physical  |        |          | f         | f      |            |      |              |
DDD/3E000000 |                     | reserved   |               | f
 barman_manual    |        | physical  |        |          | f         | f      |            |      |              |
DB6/8F000000 |                     | extended   |               | f
 barman           |        | physical  |        |          | f         | t      |     138767 |      |              |
DDD/3E000000 |                     | reserved   |               | f
(3 rows)

root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman receive-w
al --drop-slot db-manual
Dropping physical replication slot 'barman_secondary' on server 'db-manual'
Replication slot 'barman_secondary' dropped
root@mastodon ~# psql -U postgres -p 5432 -c 'SELECT * FROM pg_replication_slots;'
   slot_name   | plugin | slot_type | datoid | database | temporary | active | active_pid | xmin | catalog_xmin | res
tart_lsn  | confirmed_flush_lsn | wal_status | safe_wal_size | two_phase
---------------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+----
----------+---------------------+------------+---------------+-----------
 barman_manual |        | physical  |        |          | f         | f      |            |      |              | DB6
/8F000000 |                     | extended   |               | f
 barman        |        | physical  |        |          | f         | t      |     138767 |      |              | DDD
/3E000000 |                     | reserved   |               | f
(2 rows)

root@mastodon ~# psql -U postgres -p 5432 -c 'SELECT * FROM pg_replication_slots;'
   slot_name   | plugin | slot_type | datoid | database | temporary | active | active_pid | xmin | catalog_xmin | res
tart_lsn  | confirmed_flush_lsn | wal_status | safe_wal_size | two_phase
---------------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+----
----------+---------------------+------------+---------------+-----------
 barman_manual |        | physical  |        |          | f         | f      |            |      |              | DB6
/8F000000 |                     | extended   |               | f
 barman        |        | physical  |        |          | f         | t      |     138767 |      |              | DDD
/3E000000 |                     | reserved   |               | f
(2 rows)

root@mastodon ~# psql -U postgres -p 5432 -c "SELECT pg_drop_replication_slot('barman_manual');"
 pg_drop_replication_slot
--------------------------

(1 row)

root@mastodon ~# psql -U postgres -p 5432 -c 'SELECT * FROM pg_replication_slots;'
    slot_name     | plugin | slot_type | datoid | database | temporary | active | active_pid | xmin | catalog_xmin |
restart_lsn  | confirmed_flush_lsn | wal_status | safe_wal_size | two_phase
------------------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+-
-------------+---------------------+------------+---------------+-----------
 barman_secondary |        | physical  |        |          | f         | t      |    1429645 |      |              |
DDD/3F000000 |                     | reserved   |               | f
 barman           |        | physical  |        |          | f         | t      |     138767 |      |              |
DDD/3F000000 |                     | reserved   |               | f
(2 rows)

root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman receive-w
al --stop db-manual
Stopped process receive-wal(66061)
root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman receive-w
al --drop-slot db-manual
Dropping physical replication slot 'barman_secondary' on server 'db-manual'
Replication slot 'barman_secondary' dropped

root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman check
 db-manual
Server db-manual:
        PostgreSQL: OK
        superuser or standard user with backup privileges: OK
        PostgreSQL streaming: OK
        wal_level: OK
        replication slot: OK
        directories: OK
        retention policy settings: OK
        backup maximum age: OK (no last_backup_maximum_age provided)
        backup minimum size: OK (117.4 GiB)
        wal maximum age: OK (no last_wal_maximum_age provided)
        wal size: OK (67.9 GiB)
        compression settings: OK
        failed backups: OK (there are 0 failed backups)
        minimum redundancy requirements: OK (have 1 backups, expected at least 0)
        pg_basebackup: OK
        pg_basebackup compatible: OK
        pg_basebackup supports tablespaces mapping: OK
        systemid coherence: OK
        pg_receivexlog: OK
        pg_receivexlog compatible: OK
        receive-wal running: OK
        archiver errors: OK
root@mastodon ~# docker compose -f ~/mastodon-deployment/docker-compose.yml exec -u barman db-backup barman backup -j 4 db-manual
Starting backup using postgres method for server db-manual in /var/lib/barman/db-manual/base/20260129T005327
Backup start at LSN: DDD/4126B038 (0000000200000DDD00000041, 0026B038)
Starting backup copy via pg_basebackup for 20260129T005327
^BdCopy done (time: 20 minutes, 32 seconds)
Finalising the backup.
Backup size: 118.2 GiB
Backup end at LSN: DDD/4E01AA50 (0000000200000DDD0000004E, 0001AA50)
Backup completed (start time: 2026-01-29 00:53:27.144943, elapsed time: 20 minutes, 32 seconds)

root@mastodon ~# df -h | grep /mnt
                        300.0G    119.5G    180.5G  40% /mnt/db
                          1.5T    376.9G      1.1T  25% /mnt/barman
                        100.0G     10.6G     89.4G  11% /mnt/elastic
root@mastodon ~# du -hd2 /mnt/barman/ /mnt/db/
9.0K	/mnt/barman/data/.aws
198.3G	/mnt/barman/data/db
26.0K	/mnt/barman/data/.ssh
178.6G	/mnt/barman/data/db-manual
376.9G	/mnt/barman/data
376.9G	/mnt/barman/
8.1M	/mnt/db/mailpit
193.6M	/mnt/db/redis
1.0M	/mnt/db/data/global
512	/mnt/db/data/pg_commit_ts
512	/mnt/db/data/pg_tblspc
512	/mnt/db/data/pg_twophase
512	/mnt/db/data/pg_notify
512	/mnt/db/data/pg_serial
7.0M	/mnt/db/data/pg_multixact
512	/mnt/db/data/pg_dynshmem
9.5K	/mnt/db/data/pg_replslot
225.0K	/mnt/db/data/pg_subtrans
10.0K	/mnt/db/data/pg_logical
515.3M	/mnt/db/data/pg_wal
146.5K	/mnt/db/data/pg_stat_tmp
512	/mnt/db/data/pg_snapshots
45.4M	/mnt/db/data/pg_xact
118.8G	/mnt/db/data/base
512	/mnt/db/data/pg_stat
119.3G	/mnt/db/data
119.5G	/mnt/db/