Hello.
I am having an issue with multiple TrueNAS Scale NAS servers after the upgrade to 25.04 (Fangtooth)
On version 24.xx everything was working fine.
The issue is that Storage is not properly detected, Zpool status is reporting that is downgraded and there are no mount points listed in storage section. All of this was working perfectly fine with 24.xx
The output of configurations :
librenms@ubuntu:~$ ./validate.php
| Component | Version |
|---|---|
| LibreNMS | 25.10.0-dev.59+f7ae9821a (2025-10-10T01:34:06+04:00) |
| DB Schema | 2025_09_17_101816_add_timestamp_indexes_to_device_outages_table (356) |
| PHP | 8.3.25 |
| Python | 3.10.12 |
| Database | MariaDB 10.6.22-MariaDB-0ubuntu0.22.04.1 |
| RRDTool | 1.7.2 |
| SNMP | 5.9.1 |
| =========================================== |
[OK] Composer Version: 2.8.12
[OK] Dependencies up-to-date.
[OK] Database Connected
[OK] Database Schema is current
[OK] SQL Server meets minimum requirements
[OK] lower_case_table_names is enabled
[OK] MySQL engine is optimal
[OK] Database and column collations are correct
[OK] Database schema correct
[OK] MySQL and PHP time match
[OK] Active pollers found
[OK] Dispatcher Service is enabled
[OK] Locks are functional
[OK] Python wrapper cron entry is not present
[OK] Redis is unavailable
[OK] rrdtool version ok
[OK] Connected to rrdcached
Output of /opt/librenms/logs/librenms.log :
[2025-10-10T10:31:44][CRITICAL] Exception: TypeError LibreNMS\Util\Number::fillMissingRatio(): Argument #6 ($multiplier) must be of type int|float, string given, called in /opt/librenms/app/Models/Storage.php on line 41 @ /opt/librenms/LibreNMS/Util/Number.php:310
#0 /opt/librenms/app/Models/Storage.php(41): LibreNMS\Util\Number::fillMissingRatio()
#1 /opt/librenms/LibreNMS/OS/Traits/YamlStorageDiscovery.php(62): App\Models\Storage->fillUsage()
#2 [internal function]: LibreNMS\OS->LibreNMS\OS\Traits{closure}()
#3 /opt/librenms/LibreNMS/Discovery/YamlDiscoveryDefinition.php(165): call_user_func()
#4 /opt/librenms/LibreNMS/OS/Traits/YamlStorageDiscovery.php(70): LibreNMS\Discovery\YamlDiscoveryDefinition->discover()
#5 /opt/librenms/LibreNMS/OS/Truenas.php(13): LibreNMS\OS->discoverYamlStorage()
#6 /opt/librenms/LibreNMS/Modules/Storage.php(61): LibreNMS\OS\Truenas->discoverStorage()
#7 /opt/librenms/includes/discovery/storage.inc.php(9): LibreNMS\Modules\Storage->discover()
#8 /opt/librenms/includes/discovery/functions.inc.php(171): include(‘…’)
#9 /opt/librenms/discovery.php(107): discover_device()
#10 {main}
I wrote a small script that did the analysis.
Librenms is still fetching data as it was but multiple things got broken with TrueNAS scale update on their side.
TrueNAS Scale 25.04 (Fangtooth) - LibreNMS Storage Discovery Issues
Summary
TrueNAS Scale 25.04 (Fangtooth) introduced breaking changes to the SNMP MIB implementation that cause multiple issues with LibreNMS storage discovery and monitoring.
Environment
- TrueNAS Scale Version: 25.04.2.4 (Fangtooth)
- LibreNMS Version: 25.10.0-dev.59+f7ae9821a
- OS: Ubuntu 22.04 LTS
- SNMP Version: v2c
- MIB: FREENAS-MIB
Issue #1: Storage Discovery TypeError (CRITICAL) 
FIXED
Symptoms
- Storage discovery fails completely
- No zpools detected in LibreNMS interface
- Error in logs:
TypeError: Argument #6 ($multiplier) must be of type int|float, string given - Storage tab shows “Storage downgraded” or empty
Root Cause
TrueNAS Scale 24.xx (Working):
FREENAS-MIB::zpoolAllocationUnits.1 = 1024
FREENAS-MIB::zpoolAllocationUnits.2 = 1024
TrueNAS Scale 25.04 (Broken):
FREENAS-MIB::zpoolAllocationUnits.1 = "ONLINE"
FREENAS-MIB::zpoolAllocationUnits.2 = "ONLINE"
The OID .1.3.6.1.4.1.50536.1.1.1.1.3 (zpoolAllocationUnits) now returns the pool status string instead of a numeric allocation unit size.
Technical Details
Location: /opt/librenms/app/Models/Storage.php
Method: fillUsage()
Line: 41
The method passes $this->storage_units directly to Number::fillMissingRatio() which expects int|float as the 6th parameter ($multiplier). When TrueNAS returns “ONLINE”, this causes a TypeError.
Solution Implemented
Added validation in Storage.php line 38-44:
public function fillUsage($used = null, $total = null, $free = null, $percent = null): self
{
// Handle non-numeric multipliers (TrueNAS 25.04 returns "ONLINE" instead of numeric units)
$multiplier = $this->storage_units;
if (!is_numeric($multiplier) || $multiplier == 0) {
// If units is not numeric or zero, default to 1 to use raw values
// This handles cases where zpoolAllocationUnits contains status strings like "ONLINE"
$multiplier = 1;
}
try {
[$this->storage_size, $this->storage_used, $this->storage_free, $this->storage_perc]
= Number::fillMissingRatio($total, $used, $free, $percent, 0, $multiplier);
} catch (InsufficientDataException $e) {
Log::debug($e->getMessage());
return $this;
}
return $this;
}
Results After Fix
Storage discovery completes without errors
Storage items appear in LibreNMS interface:
/(root filesystem)/mnt/.ix-apps/docker/mnt/.ix-apps/truenas_catalog/mnt/.ix-apps/app_configs/mnt/.ix-apps/app_mounts
Status: FIXED - Patch working successfully
Issue #2: ZPool Health State Incorrect (CRITICAL) :cross_mark: UNFIXED
Symptoms
- ZPool state sensors show “Unknown” instead of “Online”
- State monitoring non-functional
- Cannot detect pool degradation or failures
Root Cause
Expected Values (FREENAS-MIB definition):
zpoolHealth:
0 = online
1 = degraded
2 = faulted
3 = offline
4 = unavail
5 = removed
TrueNAS Scale 24.xx (Working):
FREENAS-MIB::zpoolHealth.1 = 0
FREENAS-MIB::zpoolHealth.2 = 0
TrueNAS Scale 25.04 (Broken):
FREENAS-MIB::zpoolHealth.1 = 2489339904
FREENAS-MIB::zpoolHealth.2 = 9524469760
The OID .1.3.6.1.4.1.50536.1.1.1.1.7 (zpoolHealth) now returns random/corrupted large integer values instead of the documented state enum (0-5).
SNMP Query Results
$ snmpwalk -v2c -c COMMUNITY 192.168.120.206 .1.3.6.1.4.1.50536.1.1.1.1.7
iso.3.6.1.4.1.50536.1.1.1.1.7.1 = Counter64: 2489339904
iso.3.6.1.4.1.50536.1.1.1.1.7.2 = Counter64: 9524469760
Impact
- :cross_mark: Pool health monitoring non-functional
- :cross_mark: Cannot detect degraded pools
- :cross_mark: Cannot detect faulted drives
- :cross_mark: State sensors show “Unknown”
- :cross_mark: Alerting for pool issues broken
Status: :cross_mark: UNFIXED - Requires TrueNAS fix or LibreNMS workaround
Discovery Output Comparison
TrueNAS Scale 24.xx (Working)
zpoolIndex.1 = 1
zpoolIndex.2 = 2
zpoolDescr.1 = "BACKUP1"
zpoolDescr.2 = "boot-pool"
zpoolAllocationUnits.1 = 1024 ← Numeric
zpoolAllocationUnits.2 = 1024 ← Numeric
zpoolSize.1 = 10177
zpoolSize.2 = 13266
zpoolUsed.1 = 18151
zpoolUsed.2 = 2112
zpoolAvailable.1 = 54689792
zpoolAvailable.2 = 294092800
zpoolHealth.1 = 0 ← Valid enum
zpoolHealth.2 = 0 ← Valid enum
TrueNAS Scale 25.04 (Broken)
zpoolIndex.1 = 1
zpoolIndex.2 = 2
zpoolDescr.1 = "BACKUP1"
zpoolDescr.2 = "boot-pool"
zpoolAllocationUnits.1 = "ONLINE" ← String! (FIXED)
zpoolAllocationUnits.2 = "ONLINE" ← String! (FIXED)
zpoolSize.1 = 10177
zpoolSize.2 = 13266
zpoolUsed.1 = 18151
zpoolUsed.2 = 2112
zpoolAvailable.1 = 54689792
zpoolAvailable.2 = 294092800
zpoolHealth.1 = 2489339904 ← Corrupted! (UNFIXED)
zpoolHealth.2 = 9524469760 ← Corrupted! (UNFIXED)
Affected OIDs
| OID | Name | Expected Type | 24.xx Returns | 25.04 Returns | Status |
|---|---|---|---|---|---|
.1.3.6.1.4.1.50536.1.1.1.1.3.x |
zpoolAllocationUnits | INTEGER | 1024 | “ONLINE” | FIXED |
.1.3.6.1.4.1.50536.1.1.1.1.7.x |
zpoolHealth | INTEGER (0-5) | 0 | 2489339904 | :cross_mark: UNFIXED |
Files Modified
LibreNMS Patch
- File:
/opt/librenms/app/Models/Storage.php - Lines Changed: 38-44 (6 lines added)
- Impact: Minimal - only affects the
fillUsage()method - Backward Compatible: Yes - works with both 24.xx and 25.04
Testing & Verification
Test Environment
- Multiple TrueNAS Scale 25.04.2.4 servers
- LibreNMS 25.10.0-dev.59
- SNMP v2c monitoring
Verification Commands
# 1. Verify patch applied
grep -A 5 "Handle non-numeric multipliers" /opt/librenms/app/Models/Storage.php
# 2. Test storage discovery
php /opt/librenms/discovery.php -h TRUENAS_IP -m storage
# 3. Check SNMP values
snmpwalk -v2c -c COMMUNITY TRUENAS_IP .1.3.6.1.4.1.50536.1.1.1.1.3 # Allocation units
snmpwalk -v2c -c COMMUNITY TRUENAS_IP .1.3.6.1.4.1.50536.1.1.1.1.7 # Health