Hello
we are currently investigating performance issue on system runing
above btrs filesystem. Is it possible, that performance is impacted by
lack of free space? Also, how to get info about real free space on btrfs
volume?
# btrfs-show /dev/sdb1
Label: opt uuid: 28a55827-e677-47a9-98d5-d31eb3d71436
Total devices 1 FS bytes used 167.83GB
devid 1 size 240.00GB used *229.25GB* path /dev/sdb1
Btrfs Btrfs v0.19
# btrfs filesystem df /opt
Data: total=213.23GB, used=165.26GB
System, DUP: total=8.00MB, used=40.00KB
System: total=4.00MB, used=0.00
Metadata, DUP: total=8.00GB, used=2.57GB
# df -h /opt
Filesystem Size Used Avail Use% Mounted on
/dev/sdb1 240G 171G 59G 75% /opt
How come that there is difference detween btrfs-show and df .. 40GB Is
the space really usead or can I claim it back? (there are no snapshots)
# btrfs subvolume list /opt
#
Thanks
michal
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Mitch Harder
2012-Jan-10 18:40 UTC
Re: real free space on btrfs volume (performance impact)
2012/1/10 Michal Suba <michal.suba@pantheon.sk>:> Hello > > we are currently investigating performance issue on system runing above > btrs filesystem. Is it possible, that performance is impacted by lack of > free space? Also, how to get info about real free space on btrfs volume? > > # btrfs-show /dev/sdb1 > Label: opt uuid: 28a55827-e677-47a9-98d5-d31eb3d71436 > Total devices 1 FS bytes used 167.83GB > devid 1 size 240.00GB used *229.25GB* path /dev/sdb1 > > Btrfs Btrfs v0.19 > > # btrfs filesystem df /opt > Data: total=213.23GB, used=165.26GB > System, DUP: total=8.00MB, used=40.00KB > System: total=4.00MB, used=0.00 > Metadata, DUP: total=8.00GB, used=2.57GB > > # df -h /opt > Filesystem Size Used Avail Use% Mounted on > /dev/sdb1 240G 171G 59G 75% /opt > > How come that there is difference detween btrfs-show and df .. 40GB Is the > space really usead or can I claim it back? (there are no snapshots) > > # btrfs subvolume list /opt > # >The btrfs-show command is being deprecated. It''s output can be easy to misunderstand, but it probably won''t be corrected since it''s going away at some point. Basically, what this is telling you is that 229.25GB is "committed" (213.23GB Data + 2 x8.00GB Metadata (because it''s duplicated) + 2 x 8.00MB System. However, all the "committed" space is not being used (which is clearer in the ''btrfs filesystem df'' command). -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 10, 2012 at 12:40 PM, Mitch Harder <mitch.harder@sabayonlinux.org> wrote:> 2012/1/10 Michal Suba <michal.suba@pantheon.sk>: >> Hello >> >> we are currently investigating performance issue on system runing above >> btrs filesystem. Is it possible, that performance is impacted by lack of >> free space? Also, how to get info about real free space on btrfs volume? >> >> # btrfs-show /dev/sdb1 >> Label: opt uuid: 28a55827-e677-47a9-98d5-d31eb3d71436 >> Total devices 1 FS bytes used 167.83GB >> devid 1 size 240.00GB used *229.25GB* path /dev/sdb1 >> >> Btrfs Btrfs v0.19 >> >> # btrfs filesystem df /opt >> Data: total=213.23GB, used=165.26GB >> System, DUP: total=8.00MB, used=40.00KB >> System: total=4.00MB, used=0.00 >> Metadata, DUP: total=8.00GB, used=2.57GB >> >> # df -h /opt >> Filesystem Size Used Avail Use% Mounted on >> /dev/sdb1 240G 171G 59G 75% /opt >> >> How come that there is difference detween btrfs-show and df .. 40GB Is the >> space really usead or can I claim it back? (there are no snapshots) >> >> # btrfs subvolume list /opt >> # >> > > The btrfs-show command is being deprecated. It''s output can be easy > to misunderstand, but it probably won''t be corrected since it''s going > away at some point.The output of "btrfs fi show /dev/whatever" is identical, and isn''t going away afaik. That said, it is easy to misinterpret, although that''s probably unavoidable while still actually presenting that information. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html