Disk space triggers and Reserved blocks

[altuhovsu]

Hello!
In the template https://git.zabbix.com/projects/ZBX/...ds%2Frelease%2 F6.0
we have

expression: |
last(/Linux by Zabbix agent/vfs.fs.dependent.size[{#FSNAME},pused])>{$VFS.FS.PUSED.MAX.CRIT:"{#FSNAME}"} and
((last(/Linux by Zabbix agent/vfs.fs.dependent.size[{#FSNAME},total])-last(/Linux by Zabbix agent/vfs.fs.dependent.size[{#FSNAME},used]))<{$VFS.FS.FREE.MIN.CRIT:"{#FSNAME}"} or timeleft(/Linux by Zabbix agent/vfs.fs.dependent.size[{#FSNAME},pused],1h,100)<1d)
​

total-used != free

Because Reserved space of a file system (tune2fs -m 0 /dev/sda1) is taken into account and not included when using the free mode.

https://www.zabbix.com/documentation/6.0/en/manual/config/items/itemtypes/zabbix_agent#virtual-file-system-data

I have got a situation with default template macros where I have 100% used space (because of 5% reserved by default) and alert was not triggered because of 5% reserved is more than default VFS.FS.FREE.MIN.CRIT

So the options:
1. Change the logic from "total-used" to "free"
2. Change default VFS.FS.FREE.MIN.CRIT to a larger vaule (to include 5%), but it hard to calculate for all the servers
3. Set Reserved space to 0 (tune2fs -m 0 /dev/sda1)

[cyber]

Just recently, there was topic about exact same... I think there is already a ticket to support to fix that template. https://support.zabbix.com/browse/ZBX-19502 you can go and upvote it... Until then, you a free to modify your template as you please and as suits you better.


but you have another option.. use xfs, not ext4.. then all calculations are OK..