Is that filesystem an LVM logical volume?
Would it be possible to try Zabbix 2.4 agent and try executing the following command:
# zabbix_agentd -t vfs.fs.size[/srv/ams/media,pfree]
Zabbix 2.4 agent implements error messages for not supported items, this is what we are looking for.
As we see, actual mount point is /dev/mapper/vg_kimstream02_data-lv_data, which had to used in the key parameter.
Closed as won't fix.
I don't agree with closure without confirmation the issue is resolved or tested by yourself.
Monitoring the mount point as suggested will reflect a different issue, the agent will return 1,525,473,280 which is not equal to 1,500,500,652,032
# df -B1 /dev/mapper/vg_kimstream02_data-lv_data
Filesystem 1B-blocks Used Available Use% Mounted on
/dev/mapper/vg_kimstream02_data-lv_data
2164338376704 1500500652032 553888870400 74% /srv/ams/media
# zabbix_get -s xxx.xxx.xxx.xxx -k vfs.fs.size[/dev/mapper/vg_kimstream02_data-lv_data,free]
1525473280
Anyway the agent should be able to read the size of /srv/ams/media 
.
'Template OS Linux' has automatically discovered all partitions of this server. They are created with logical volumes and the problem occurs with the large partition only (1 of 7), all other 6 partitions can be monitored:
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_kimstream02-lv_root
16G 2,2G 13G 16% /
tmpfs 1,5G 72K 1,5G 1% /dev/shm
/dev/sda1 477M 139M 313M 31% /boot
/dev/mapper/vg_kimstream02-lv_home
16G 41M 15G 1% /home
/dev/mapper/vg_kimstream02-lv_opt
16G 493M 14G 4% /opt
/dev/mapper/vg_kimstream02-lv_tmp
7,6G 22M 7,2G 1% /tmp
/dev/mapper/vg_kimstream02-lv_usr
16G 3,3G 12G 23% /usr
/dev/mapper/vg_kimstream02-lv_var
16G 284M 15G 2% /var
/dev/mapper/vg_kimstream02_data-lv_data
2,0T 1,4T 516G 74% /srv/ams/media
For example the agent returns the size for the /opt partition as expected:
# df -h /opt
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_kimstream02-lv_opt
16G 493M 14G 4% /opt
# zabbix_get -s xxx.xxx.xxx.xxx -k vfs.fs.size[/opt,free]
15024648192
The agent returns for /opt the exact size of free space 15,024,648,192:
# df -B1 /dev/mapper/vg_kimstream02-lv_opt
Filesystem 1B-blocks Used Available Use% Mounted on
/dev/mapper/vg_kimstream02-lv_opt
16379748352 516239360 15024648192 4% /opt
# zabbix_get -s xxx.xxx.xxx.xxx -k vfs.fs.size[/opt,free]
15024648192
Heh, I don't know how that could happen, but I was wrong, I'm sorry.
The /dev/mapper/vg_kimstream02_data-lv_data is actually a block device, and /srv/ams/media should be a file system.
And now I'm getting surprised that block devices for vfs.fs.size return some values 
. I've just reported it in ZBX-10188.
A test on my side:
# df -B1 / Filesystem 1B-blocks Used Available Use% Mounted on /dev/sda2 196568788992 186131685376 10437103616 95% / # zabbix_get -s localhost -k vfs.fs.size[/,free] 10437103616 # zabbix_get -s localhost -k vfs.fs.size[/,used] 186131685376 # zabbix_get -s localhost -k vfs.fs.size[/dev/sda2,free] 10485760 # zabbix_get -s localhost -k vfs.fs.size[/dev/sda2,used] 0
Well, as Aleksandrs Saveljevs requested, please test recent agent version 2.4.7
No problem, I am happy that you could reproduce one issue. I am going to test with agent version 2.4.7 if required, but after mid January. Would an agent 2.4 work with server 2.2?
Your root partition you've tested is smaller than 1TB (it is ~190GB large), your test may be or may be not relevant. But because /srv/ams/media is a iSCSI target, I am wondering if it may cause the trouble rather than the agent version. Could you test this scenario?
Please change the environment setup to CentOS 2.6.32-573.12.1.el6.x86_64 (sorry for confusion).
yes, agent 2.4 is absolutely compatible with lower zabbix server/proxy.
I don't think that partition size does the key matter, probably something else.
For example in https://support.zabbix.com/browse/ZBX-3640#comment-40980 are my success tests for ~6TB iSCSI targets, although connected to a windows host.
Sorin, check please also first Aleksandrs Saveljevs' comment and do exactly what was requested (zabbix_agentd -t ....), as in such a way the check performed under a shell user, for example root.
This way you can run it also with "strace" command and maybe notice something useful.
yes, agent 2.4 is absolutely compatible with lower zabbix server/proxy.
Just a note that, while probably true, using a newer agent with an older server/proxy is not officially supported. Using an older agent with a newer server/proxy is.
The problem is reproducible in 2.4 with the following error:
- zabbix_get -s xxx.xxx.xxx.xxx -k vfs.fs.size[/srv/ams/media/,free]
ZBX_NOTSUPPORTED: Cannot obtain filesystem information: [13] Permission denied
After the permissions for 'zabbix' user were changed request returned the expected values:
- zabbix_get -s xxx.xxx.xxx.xxx -k vfs.fs.size[/srv/ams/media/,free]
543421341696
The problem is solved, the error messages from 2.4 helped to isolate the issue as suggested. Thank you!
—
As regards your ticket ZBX-10188 (already closed) is seems that 'zabbix_get' cannot get the right values for the
devices (in my case the logical volume) but for the directory (the mounted point).
Do you recommend to use Zabbix 2.2 or 2.4?
hmm. 2.4 provides more details in case if item is not supported, so it's better.
I'm closing this issue as cannot reproduce.