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raspi
Asked: 2011-04-24 12:46:18 +0800 CST

How to monitor ZFS with SNMP in FreeBSD?

  • 772

I'd like to monitor these with SNMP:

zpool iostat -v 1

Per drive and sum.

zpool status

Scrubbing as 1 and not scrubbing as 0. 

zpool status -x

Monitor $? (return value). Send trap when value is not 0.

zfs list

Used & free space.

What kind of scripts are needed?

snmp freebsd zfs

2 Answers

  1. Best Answer

    Assuming you're using net-snmpd, you'd probably need to write a script per value. Then, using the techniques described in the snmpd.conf man page, section 'extending agent functionality', add references of those scripts to your snmpd.conf.

    For example, /root/bin/myzstatus:

    #!/bin/sh
/sbin/zpool status -x $1

    and in snmpd.conf:

    extend status /root/bin/myzstatus tank

    With zfs/zpool, you're blessed since most of the subcommands have options for machine output, which will make it easier to grok.

    • 2

  2. I don't know the answer for the zpool status, scrub, etc. but for space I figured something out.

    in /etc/snmpd.config, I found this, and uncommented it, and now I have storage values:

    #
# Host resources module
#  This requires the mibII module.
#
begemotSnmpdModulePath."hostres" = "/usr/lib/snmp_hostres.so"

    And here is some output:

    # snmpwalk -v1 -c public $freebsdzfsmachine | grep -E "Storage.*\.22 " | less
HOST-RESOURCES-MIB::hrStorageIndex.22 = INTEGER: 22
HOST-RESOURCES-MIB::hrStorageType.22 = OID: HOST-RESOURCES-TYPES::hrFSOther
HOST-RESOURCES-MIB::hrStorageDescr.22 = STRING: /tank, type: zfs, dev: tank
HOST-RESOURCES-MIB::hrStorageAllocationUnits.22 = INTEGER: 512 Bytes
HOST-RESOURCES-MIB::hrStorageSize.22 = INTEGER: 2147483647
HOST-RESOURCES-MIB::hrStorageUsed.22 = INTEGER: 1030063349
HOST-RESOURCES-MIB::hrStorageAllocationFailures.22 = Counter32: 0
HOST-RESOURCES-MIB::hrFSStorageIndex.22 = INTEGER: 24

    Unfortunately, the Size output (1024 GiB) is wrong. Storage size according to df is 20 TiB and used is 491 GiB, but for some reason, Size here is coincidentally exactly 2^31-1 * 512 bytes. (where 2^31-1 is the maximum value of a signed 32 bit integer). Used is correct though: 1030063349*512/1024/1024/1024 = 491.

    Fortunately though, it works fine for my 80 GB root disk. I guess it is limited to 1 TiB on FreeBSD. This same mount seen using SNMP on a Linux NFS client shows the correct value and hrStorageAllocationUnits is "INTEGER: 32768 Bytes"

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