[Bug 297408] [zfs] pool checkpoint can eat up all available and unreasonable amount of space
Date: Sun, 09 Aug 2026 22:16:10 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=297408
Bug ID: 297408
Summary: [zfs] pool checkpoint can eat up all available and
unreasonable amount of space
Product: Base System
Version: 15.1-RELEASE
Hardware: Any
OS: Any
Status: New
Severity: Affects Only Me
Priority: ---
Component: kern
Assignee: bugs@FreeBSD.org
Reporter: emz@norma.perm.ru
FreeBSD 15.1-RELEASE. First seen on 15.0-RC1.
Each noon the following shell script works from cron:
===Cut===
for pool in zroot data
do
zpool checkpoint -d -w $pool || true
zpool checkpoint $pool
done
[dataset snapshotting and snapshot rotation]
===Cut===
Once in several days (like 7-10) the checkpoint eats up all of the available
space, and we're talking terabytes:
# zpool status
pool: data
state: ONLINE
checkpoint: created Mon Aug 10 00:00:00 2026, consumes 3.61T
config:
NAME STATE READ WRITE CKSUM
data ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
nda0 ONLINE 0 0 0
nda1 ONLINE 0 0 0
nda2 ONLINE 0 0 0
nda3 ONLINE 0 0 0
errors: No known data errors
Under normal conditions the pool is about 50% used:
# zpool list
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH
ALTROOT
data 14.0T 7.70T 6.27T - - 34% 55% 1.00x ONLINE -
zroot 1.72T 192G 1.53T 5.61M - 5% 10% 1.00x ONLINE -
The pool normally holds small amount of daily rotated snapshots. Snapshotting,
their rotation and zpool checkpointing all take place from one single script
running commands sequentially.
Dataset layout:
# zfs list -t all
NAME USED AVAIL REFER MOUNTPOINT
data 5.60T 4.43T 140K /data
data/attic 407G 4.43T 407G
/usr/local/public/attic
data/mongodb 1.37T 4.43T 1.37T /var/db/mongodb
data/mongodb@06-08-2026 442K - 1.37T -
data/mongodb@07-08-2026 494K - 1.37T -
data/mongodb@08-08-2026 494K - 1.37T -
data/mongodb@09-08-2026 465K - 1.37T -
data/mongodb@10-08-2026 418K - 1.37T -
data/mysql 3.69T 4.43T 3.62T /var/db/mysql
data/mysql@06-08-2026 14.8G - 3.61T -
data/mysql@07-08-2026 8.57G - 3.62T -
data/mysql@08-08-2026 8.22G - 3.62T -
data/mysql@09-08-2026 8.12G - 3.62T -
data/mysql@10-08-2026 6.85G - 3.63T -
zroot 192G 1.48T 96K /zroot
zroot/ROOT 8.40G 1.48T 96K none
zroot/ROOT/default 8.40G 1.48T 8.40G /
zroot/home 420M 1.48T 398M /home
zroot/home/emz 22.5M 1.48T 22.5M /home/emz
zroot/tmp 22.8M 1.48T 22.8M /tmp
zroot/usr 58.1G 1.48T 96K /usr
zroot/usr/local 49.5G 1.48T 2.07G /usr/local
zroot/usr/local/etc 1.38M 1.48T 1.38M /usr/local/etc
zroot/usr/local/public 47.4G 1.48T 104K
/usr/local/public
zroot/usr/local/public/jails 47.4G 1.48T 112K
/usr/local/public/jails
zroot/usr/local/public/jails/php74 32.2G 1.48T 9.33G
/usr/local/public/jails/php74
zroot/usr/local/public/jails/php74@reloc 22.8G - 32.1G -
zroot/usr/local/public/jails/php84 7.45G 1.48T 7.45G
/usr/local/public/jails/php84
zroot/usr/local/public/jails/php84@reloc 336K - 7.45G -
zroot/usr/local/public/jails/php85 7.77G 1.48T 7.44G
/usr/local/public/jails/php85
zroot/usr/local/public/jails/php85@reloc 337M - 6.95G -
zroot/usr/ports 5.74G 1.48T 5.74G /usr/ports
zroot/usr/src 2.92G 1.48T 2.92G /usr/src
zroot/var 125G 1.48T 96K /var
zroot/var/audit 96K 1.48T 96K /var/audit
zroot/var/crash 96K 1.48T 96K /var/crash
zroot/var/db 231M 1.48T 96K /var/db
zroot/var/db/mongodb-config 231M 1.48T 209M
/var/db/mongodb-config
zroot/var/db/mongodb-config@29-03-2026 320K - 211M -
zroot/var/db/mongodb-config@30-03-2026 252K - 216M -
zroot/var/db/mongodb-config@31-03-2026 324K - 210M -
zroot/var/db/mongodb-config@01-04-2026 272K - 215M -
zroot/var/db/mongodb-config@02-04-2026 0B - 209M -
zroot/var/db/mongodb-config@06-08-2026 0B - 209M -
zroot/var/db/mongodb-config@07-08-2026 0B - 209M -
zroot/var/db/mongodb-config@08-08-2026 0B - 209M -
zroot/var/db/mongodb-config@09-08-2026 0B - 209M -
zroot/var/db/mongodb-config@10-08-2026 0B - 209M -
zroot/var/log 2.21M 1.48T 2.21M /var/log
zroot/var/mail 4.21M 1.48T 4.21M /var/mail
zroot/var/tmp 296K 1.48T 296K /var/tmp
zroot/var/www 125G 1.48T 123G /var/www
zroot/var/www@13-03-2026 83.2M - 124G -
zroot/var/www@14-03-2026 79.4M - 124G -
zroot/var/www@15-03-2026 59.7M - 124G -
zroot/var/www@16-03-2026 41.4M - 124G -
zroot/var/www@17-03-2026 338M - 124G -
zroot/var/www@06-08-2026 0B - 123G -
zroot/var/www@07-08-2026 0B - 123G -
zroot/var/www@08-08-2026 0B - 123G -
zroot/var/www@09-08-2026 0B - 123G -
zroot/var/www@10-08-2026 0B - 123G -
The server runs Mysql database.
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