Storage
banshee/storage-collection/storage/truenas/snmp/core/
datasets
The space of each ZFS dataset of a TrueNAS CORE by SNMP (FREENAS-MIB).
par banshee1 installation2 versions
v2Dernière
Publiée le 28 octobre 2026. One naming convention across collections; documentation completed.
Datasets of a TrueNAS CORE, by SNMP
Returns, for each ZFS dataset of a TrueNAS CORE, its used space, its free space and its size. Four watches are offered, each one set on the probe.
Versions
Written for FREENAS-MIB, revision 2020-05-28: the MIB of TrueNAS CORE 12 and 13, and of TrueNAS SCALE up to 22.12. TRUENAS-MIB, served by TrueNAS SCALE 23.10 to 25.10, has no dataset table. Hence the folder core.
How it works
The collector reads one table of FREENAS-MIB, datasetTable (1.3.6.1.4.1.50536.1.2.1):
| Column | OID | Read as |
|---|---|---|
datasetDescr | .1.2 | the dataset's name (tank/home), the instance |
datasetAllocationUnits | .1.3 | bytes per unit |
datasetUsed, datasetAvailable | .1.5, .1.6 | counts of units |
- A dataset's size is its used space plus its available space: its quota when it has one, or what the pool has left. Datasets without a quota share the pool's free space: they all fill up together.
- The pool's root dataset (
tank) is a dataset like the others. - The collector only reads: SNMP sends nothing but reads.
Prerequisites
- The SNMP service of TrueNAS enabled (Services, SNMP), reachable from the poller (UDP 161), its access restricted to the poller.
- Read-only access, SNMPv2c or SNMPv3, set on the host or one of its folders (
protocol:snmp:*variables).
Outputs
| Name | Label | Unit | Per instance |
|---|---|---|---|
used-percent | Used space | % | yes, per dataset |
free | Free space | GiB | yes, per dataset |
size | Size | GiB | yes, per dataset |
Watches
| Name | Title | Kind | Defaults | Checked by default |
|---|---|---|---|---|
used | Used space | above a threshold, on used-percent | warning above 80 %, critical above 90 % | yes |
full-soon | Full within a week | above a threshold, on used-percent | warning above 99 %, ahead 7 d | yes |
free | Little free space | below a threshold, on free | critical below 10 GiB | no |
missing | Dataset missing | expected instances, on used-percent | no dataset named: it raises nothing until names are set on the probe | no |
Limits
- An agent that serves no dataset stops the collector
misconfigured. - A TrueNAS with many datasets returns many instances: narrow the selection on the probe to the datasets that count.
- Not checked against a TrueNAS: the OIDs are those of the MIB file of TrueNAS 13.0 (
FREENAS-MIB.txt, middleware branchtruenas/13.0-stable).