[checkmk-commits] Check_MK Git: check_mk: Linux Agent: Plugin for tracking LVM volume statistics

Module: check_mk Branch: master Commit: 41678d1fe567c583c02fb27c0a16791aa3d12861 URL: http://git.mathias-kettner.de/git/?p=check_mk.git;a=commit;h=41678d1fe567c5… Author: Florian Heigl <fh(a)mathias-kettner.de> Date: Mon May 21 12:50:32 2012 +0200 Linux Agent: Plugin for tracking LVM volume statistics --- agents/plugins/lvmstat | 60 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 60 insertions(+), 0 deletions(-) diff --git a/agents/plugins/lvmstat b/agents/plugins/lvmstat new file mode 100755 index 0000000..7e6f5ef --- /dev/null +++ b/agents/plugins/lvmstat @@ -0,0 +1,60 @@ +#!/usr/bin/python + +# Agent plugin to gather io statistics on lvm volumes +# as tricky as i'd have expected. +# it seems there is no way to ask devmapper for lvm volumes only. +# (...major numbers were such an awesome idea) + + +import os +import subprocess + + +# should be a dict +# { "dm-1" : (vg01, lvol12)} +devices = {} +stats = {} + + +# grab volume groups and lv's from lvm. Otherwise we might also find devices that +# are used by "something completely different" - i.e. multipath targets +lvlist = subprocess.Popen(["lvs", + "--separator", ";", "--noheadings", + "--nosuffix", "-o", "vg_name,lv_name" ], + stdout=subprocess.PIPE) + + +# with this list from lvm we can now find the dm nodes of the volumes +for line in lvlist.stdout.readlines(): + line = line.strip() + vg_name, lv_name = line.split(";") + # Found this in dtc-xen's statistics server. Greetings to Thomas! + minor = os.minor(os.stat("/dev/%s/%s" % (vg_name, lv_name)).st_rdev) + dmdev = "dm-%s" % minor + devices.update( { dmdev : (vg_name, lv_name)}) + + + +# then we can parse our nice new dictionary and grab the stats for each blockdev +for dmdev in devices.keys(): + counter = "/sys/block/%s/stat" % dmdev + stats[dmdev] = file(counter).read().rstrip() + + # read the gathered stats and if they are showing no IO, then + # either there was the counters disabled (and we enable them) + # or there was simply no IO to the LVM volume. + + if sum(map(int, stats[dmdev].split()[3-8])) == 0: + stats_switch = "/sys/block/%s/queue/iostats" % dmdev + if map(int, file(stats_switch).read().rstrip()) == 0: + os.system("echo 1 > /sys/block/%s/queue/iostats" % dmdev) + + print ("%s/%s %s") % (devices[dmdev][0],devices[dmdev][1], stats[dmdev]) + + + + + +# BUGS: this script uses stat and open/read/close on each lvm volume. +# in large-scale systems this is quite inefficient. +# OTOH systems of that scale typically use VxVM instead of LVM.