Graph ZFS details with Cacti (Nexenta)

Today, as promised a long time ago, and therefore seriously overdue, a short writeup on how to graph ZFS details from Nexenta on Cacti.

On the Nexenta host

Firstly, add some extends to you SNMPD.CONF (here is some background on how to do this ). To do this log in (ssh) as admin to your Nexenta box, then obtain root privileges (su).

Now start  the nmc and run the command setup network service snmp-agent edit-settings . this allows you to edit the snmpd.conf file on a Nexenta host. Do not go about editing these files directly in /etc/snmp because it will not work that way

Now add your extends to the snmpd.conf file, i googled a bit to get some commands to return ZFS details, for our servers we added the following. The snmp-agent edit-settings  will open the snmpd.conf file in VI, so remember: a is to append, :x is to save, dd is to delete a line.

We added the following extends to our Nexenta server

extend . zpool_name /bin/bash -c “zpool list -H -o name”
extend . zpool_snap /bin/bash -c “zpool list -Ho name|for zpool in `xargs`;do zfs get -rHp -o value usedbysnapshots $zpool|awk -F: ‘{sum+=$1} END{print sum}';done”
extend . zpool_used /bin/bash -c “zpool list -Ho name|xargs zfs get -Hp -o value used”
extend . zpool_data_used /bin/bash -c “zpool list -Ho name|for zpool in `xargs`;do snap=`zfs get -rHp -o value usedbysnapshots $zpool|awk -F: ‘{sum+=$1} END{print sum}’`;pool=`zfs get -Hp -o value used $zpool`; echo $pool $snap|awk ‘{print (\$1-\$2);}';done”
extend . zpool_available /bin/bash -c “zpool list -Ho name|xargs zfs get -Hp -o value available”
extend . zpool_capacity /bin/bash -c “zpool list -H -o capacity”
extend . arc_meta_max /bin/bash -c “echo ::arc | mdb -k| grep arc_meta_max|tr -cd ‘[:digit:]‘”
extend . arc_meta_used /bin/bash -c “echo ::arc | mdb -k| grep arc_meta_used|tr -cd ‘[:digit:]‘”
extend . arc_size /bin/bash -c “echo ::arc | mdb -k| grep -w size|tr -cd ‘[:digit:]‘”
extend . arc_meta_limit /bin/bash -c “echo ::arc | mdb -k| grep arc_meta_limit|tr -cd ‘[:digit:]‘”
extend . arc_meta_c_max /bin/bash -c “echo ::arc | mdb -k| grep c_max|tr -cd ‘[:digit:]‘”
extend . arc_hits /bin/bash -c “kstat -p ::arcstats:hits| cut -s -f 2″
extend . arc_misses /bin/bash -c “kstat -p ::arcstats:misses| cut -s -f 2″
extend . arc_l2_hits /bin/bash -c “kstat -p ::arcstats:l2_hits| cut -s -f 2″
extend . arc_l2_misses /bin/bash -c “kstat -p ::arcstats:l2_misses| cut -s -f 2″
extend . vopstats_zfs_nread /bin/bash -c “kstat -p ::vopstats_zfs:nread | cut -s -f 2″
extend . vopstats_zfs_nwrite /bin/bash -c “kstat -p ::vopstats_zfs:nwrite | cut -s -f 2″
extend . vopstats_zfs_read_bytes /bin/bash -c “kstat -p ::vopstats_zfs:read_bytes | cut -s -f 2″
extend . vopstats_zfs_write_bytes /bin/bash -c “kstat -p ::vopstats_zfs:write_bytes | cut -s -f 2″

I know on Extends you normally would not have to provide an OID, but I like to provide them anyway so I know where to look for the SNMP OID.

After adding these, save the file and say yes to the question to reload the file after the save. Now check the configuration with:

setup network service snmp-agent confcheck

and then restart the snmpd with:

setup network service snmp-agent restart

Your work is now done on the Nexenta host, you can check the settings with an snmpwalk command to see if it actually works


I assume you have an SNMP enabled device set up to point to your Nexenta server, if not this would be a good time to do so. SNMP V2c works for me.

Now import the following XML graph templates on the end of this post to your Cacti server (I’ve got these from this forum but had to modify them quite a bit for them to see get the data form the correct SNMP OID’s.

Now add these templates to your device, and create the graphs. If you are lucky you will get some pretty pictures with some usefull information, especially the one on L2ARC cache turned out to be quite useful to us.

Good luck, and if you have any questions, post  them.



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VMware tools on Ubuntu 12.04 LTS from Repository

Task for today, equip a couple of dozen VM’s with VMware Tools. I hate manual labor so I hacked up this little script.

Make sure current VMware tools or open-vm tools are uninstalled and purged otherwise this will crap out.

# Fetch the key

apt-get install python-software-properties –yes
apt-key add

# Add the Repo to APT, and remove sources (we remove all sources, but you can specify to remove only
# VMware sources (since they are not published and will end up in an error)

apt-add-repository ‘deb precise main’ && wait
# We dont want any sources by default
sed -i ‘s/deb-src/#deb-src/g’ /etc/apt/sources.list


# Install the tools

apt-get update &&
# Check Kernel version, we use 12.04 LTS ONLY, esx-nox is NO GFX support, as it should be
apt-get install vmware-tools-esx-kmods-3.2.0-23-generic vmware-tools-esx-nox –yes &&
apt-get upgrade –yes && wait


Ce’st ca, all done.

How to install ESXi on those darn cheap-ass SanDisk Cruzer fit sticks

It took me some time to figure out, but for my next batch of ESXi hosts for our cloud platform I simply refused to go to the WanChai computer center again to buy new USB sticks, as I still had a batch of those SanDisk Cruzer Fit sticks lying around from my previous attempt. Last time, because of time constraints, I had to take the easy route and go and buy HP branded stuff for our army of BL495. But today we received another 16 or so 495’ers to fill up another enclosure, and as said, I refused to go out to the computer-center to buy sticks again, it bloody pouring out there :)

So I dug in to this and with a little help from google and the syslog logs, I figured it out, It seems that ESXi wan’t to format the USB stick with a GPT partition, which some sticks like these SanDisk Cruzers, won’t take. Now to force the installed to use classic MBR, upon install, on the boot screen press SHIFT-O for the boot options of runweasel.

Remove whatever you see there and just replace it with runweasel formatwithmbr press enter, and voila, your install will proceed, format the stick, install the binaries, and most important, boot from it on next reboot.



Cisco 7961 headaches

Man, I never liked Cisco stuff, and after today my esteem for the SF router and switch giant has dropped another notch.  Why?. well try to get a Cisco 7961 (or 7960 for that matter) work in Asterisk, then you’ll understand. So to ease the burden of some of you out there that try to do the same, here is the Asterisk  / FreePBX template that finally made it work for me.

We used the freely available SIP41.8-4-3S fimware, just create yourself an account on Cisco support and fetch it, we tried some of the 9 versions without any luck, so stick to the 8 versions i’d say, works just fine.

Also as other blogs outline in great detail, <natEnabled>false</natEnabled> seem to be quite important :),

well good luck…

<?xml version="1.0" ?>
 <timeZone>China Standard/Daylight Time</timeZone>
 <member priority="0">
 <line button="{$line}">

No more Nexenta CPU overload

We have all seen it, NexentaStor eating away the CPU in an ESXi environment. It’s actually not consuming the CPU cycles, but since Illuminos reserves cycles (basically telling the CPU to go through a zillion NOOPS) the CPU get trashed, eating up to 15% for each core. Not a pretty sight, and certainly something you would want to get rid off since this seriously screws up your ESXi resource scheduler.

How to go about this is actually quite easy, just disable the nmdtrace service. One small down side to that though, removing / disabling this service will kill all performance stats in the NMS, not that they are of any use anyways, they are nothing short of pathetic (sorry Nexenta), to get around that I will describe how to extend SNMP to get proper statistics into something like Cacti in a later post.

First, lets free up those NOOP cycles and kill nmdtrace. Before doing so you would like to remove the dependency of it with the NVM, so here goes (all as SU on the console of your Nexenta box of course)

svccfg -s nmv delpg nmdtrace

check the NVM service for state

svcs nmv

And if necessary, remove failure state by

svcadm clear nmv

svcadm refresh  nmv

Now we are good to go to kill the nmdtrace process by issuing

svcadm disable -s nmdtrace

If you would like to enable it (god knows why) just issue

svcadm enable s nmdtrace

See the pretty graph :)







Local Ubuntu Mirror

We were getting tired of our Ubuntu server reaching out to the internet every day/week to fetch updates and patches. Man if you though Windoze was bad, these Ubuntu servers know their way around consuming bandwidth as well. So in the Windoze world we had something called WSUS (if it is still called that?) so i wanted something similar to keep roughly 150+ servers from going out to fetch their bits.

The APT-MIRROR package to the rescue. Setup is quite easy, but i did not find any ‘cook book’ that fitted all my needs.

First off I need to store these mirrors on a nice de-duplicated NFS server (Nexenta/ZFS) to keep it from consuming to many GB’s. So what we did is create a NFS export on one of our SAN’s with root access for the Mirror server, simple enough.

On the server side

On the server we install APT-MIRROR with a simple apt-get command;

apt-get install apt-mirror

This installs the package and creates the structure in /var/spool/apt-mirror

Now we mount our NFS mount-point to the /var/spool/apt-mirror/mirror from the FSTAB in the usual way

<hostname>:/volumes/pool1/mirror /var/spool/apt-mirror/mirror nfs auto,noatime,nolock,bg,nfsvers=3,intr,tcp,actimeo=1800 0 0

(yes, our NFS is still V3, since it serves some ESXI hosts as well)

Now it is time to configure our /etc/apt/mirror.list, we ended up with

############# config ##################
set base_path /var/spool/apt-mirror
set mirror_path $base_path/mirror
set skel_path $base_path/skel
set var_path $base_path/var
set cleanscript $var_path/
set postmirror_script $var_path/
set run_postmirror 1
set nthreads 10
set _tilde 5
set defaultarch amd64

############## end config ##############

deb precise main restricted universe multiverse
deb precise-security main restricted universe multiverse
deb precise-updates main restricted universe multiverse
deb precise-proposed main restricted universe multiverse
deb precise-backports main restricted universe multiverse
deb precise main main/debian-installer restricted restricted/debian-installer universe universe/debian-installer multiverse multiverse/debian-installer


Now how did we decide to go for to fetch our mirror, for us this was the best performing (not necessarily closest) mirror that is up-to-date. A way to determine your fastest mirror is with the handy netselect tool. how to install and use;

First fetch the latest binary (at time of writing 0.3.ds1-25


Then throw it against the mirror lists from launchpad, and add some grep magic to make the output readable

netselect -v -s10 -t20 `wget -q -O- | grep -P -B8 “statusUP|statusSIX” | grep -o -P “(f|ht)tp.*\”” | tr ‘”\n’ ‘ ‘`

For us it came back with the Hong Kong Chinese University and some others, the Taiwan repo was at the 3rd place, We decided to use the Taiwan one since the Hong Kong archives tend not up to date, maybe we should open up ours to have an up-to-date repo down one here :) . Anyway, you should verify your results against the mirror list on to get your close and up to date repo.

It is now time to do a first time population of the repository by manually executing

apt-mirror -c apt-mirror

This can take some time as we will pull down

Now the newly downloaded repo can be made available through a web server of choice (Apache for us). We just linked the ubuntu folder to the /vat/www, we could also share the folder out as an RSYNC repo on the Nexenta storage server, maybe at a later time, not today.

ln -s /var/spool/apt-mirror/mirror/ /var/www/ubuntu

Now all that is left to do on the server side is to add the update script to your cron tab for scheduled execution, this is made easy as the package provides this schedule file in /etc/cron.d/apt-mirror, the only thing you need to do there is to uncomment the line

On the Client Side

On the client side we need to edit the /etc/apt/sources.list. Here we commented every deb repo and left the deb-src pointing to the us repositories. Then on the top of the file we added the deb repe’s for our own mirror.

deb http://<domain>/ubuntu precise main restricted universe multiverse
deb http://<domain>/ubuntu precise-security main restricted universe multiverse
deb http://<domain>/ubuntu precise-updates main restricted universe multiverse
deb http://<domain>/ubuntu precise-proposed main restricted universe multiverse
deb http://<domain>/ubuntu precise-backports main restricted universe multiverse

#deb precise main restricted
deb-src precise main restricted
#deb precise-updates main restricted
deb-src precise-updates main restricted
#deb precise universe
deb-src precise universe
#deb precise-updates universe
deb-src precise-updates universe
#deb precise multiverse
deb-src precise multiverse
#deb precise-updates multiverse
deb-src precise-updates multiverse
deb-src precise-backports main restricted universe multiverse
#deb precise-backports main restricted universe multiverse
#deb precise-security main restricted
deb-src precise-security main restricted
#deb precise-security universe
deb-src precise-security universe
#deb precise-security multiverse
deb-src precise-security multiverse

now run an apt-get update / apt-get upgrade, and all should be coming from your own repo

As always, hope this helps someone save time, if it does not work out for you, pleaee  leave a comment and we’ll try to help where possible

- Fault



Cacti script to get temperatures from an ILO device.

We wanted to experiment with different airflow scenarios in our DC and did not want to get in to expensive data center power management tools, so we decided to use a simple cacti server and the ILO temperature measurements from servers in certain spots in the racks to get a historic graph of inflow air temperatures, you get the idea.

But man!, Cacti can be a pain in the butt!, and so can be the HP/ILO SNMP implementation. As you might have noticed the SNMP/OID does not push out measured temperature sensors, sigh.. To get around this hurdle we had to hack up a quick script, and since it took me quite some time to google all components together i’d thought why not put them here for others to enjoy, saving the world some time here.

Our setup, a simple vanilla Ubuntu 12.04 LTS VM,  with Cacti from the Ubuntu Repo (0.8.7i), I assume I don’t need to explain how to set this up. So to get stuff working, first we get the HP Lights-Out XML PERL Scripting Sample (I fetched this one) for Linux, untar and install.

Copy out the files Get_EmHealth.xml and to the /usr/share/cacti/site/scripts folder, chown them to root (as Cacti runs its scripts as root)

Add your ILO credentials to the EmHealth.xml, I could go as far as parameterizing them for Cacti to provide, but since we use the same across all ILO’s in a separate management network, i did not bother

<LOGIN USER_LOGIN=”your user name” PASSWORD=”your password“>

Next, I created this little PERL script

$command = “/usr/bin/perl -X /usr/share/cacti/site/scripts/ -s $ARGV[0] -f /usr/share/cacti/site/scripts/Get_EmHealth.xml”;

#$command = “/usr/bin/perl -X /usr/share/cacti/site/scripts/ -s -f /usr/share/cacti/site/scripts/Get_EmHealth.xml”;

$output = `$command`;

@lines = split(/\n/,$output);

foreach $line(@lines){
if (index ($line ,”LOCATION VALUE”) != -1) {
$line =~ s/\s+/_/g;
if ($line =~ /”(.+?)”/) { print”$1:”;}}
if (index ($line ,”CURRENTREADING VALUE”) != -1) {
if ($line =~ /”(.+?)”/) { print”$1 “;}}

What this basically does is parse the XML (ish) output from, find the Location Value and CurrentReading Value (which are sensors and values) and write them out as a valid Cacti script return string for by DL385g5 this is:

CPU:62 CPU_1:50 CPU_2:44 Memory_a:57 Memory_b:46 System:62 Ambient:21

As you can see I also trip out all spaces and replace them by underscores to keep the output valid for Cacti. So now we can run this script in a Cacti Data Input Method, see this link on how to do that, and as long as we provide the EXACT output fields, we will get values back to push in to RDD. I am only interested in the Ambient sensors, but maybe you like to graph more..

Hope this helps someone save some time





Setting IOPS for HP/EVA devices, the dirty ESXCLI way.

Stumbled upon the “Best practices for HP EVA, vSphere 4 and Round Robin multi-pathing” by Ivo Beerens or the VMware community article “Very slow performance on EVA4400” and wondered how to hack this in to an ESXi box without a service console. (tried Ivo’s solution in the ‘Engineering SSH shell, but for some reason it failed on the grep command’. Of course you can use the horrid windows power(s)hell and fiddle around with that, or for dinosours like me that live in old DOS/Command line worlds, download the VMware ESXCLI package for windoze (or Linux, but then this script wont work)  and copy and paste this script in to a .cmd file

@echo off
esxcli --server <hostname> --username=root --password=*** nmp device list | find "HP Fibre Channel Disk" >dev.lst
for /F "tokens=1,2 delims=()" %%G IN (dev.lst) DO esxcli --server <hostname> --username=root --password=Nipples@Sandpaper nmp roundrobin setconfig --type "iops" --iops=1 --device=%%H
del dev.lst

Remember to replace the obvious username,password and servername values and off you go!.

Of course you can get creative and make a loop around this to go through your servers automatically, but I had only 8 to worry about so I didn’t bother.

Good luck,

– Fault


A paraprosdokian is a figure of speech in which the latter part of a sentence or phrase is surprising or unexpected in a way that causes the reader or listener to reframe or reinterpret the first part. It is frequently used for humorous or dramatic effect, sometimes producing an anticlimax. e.g. “Where there’s a will, I want to be in it.” (Wikipedia)

1. Do not argue with an idiot. He will drag you down to his level and beat you with experience.
2. The last thing I want to do is hurt you. But it’s still on my list.
3. Light travels faster than sound. This is why some people appear bright until you hear them speak.
4. If I agreed with you, we’d both be wrong.
5. We never really grow up, we only learn how to act in public.
6. War does not determine who is right – only who is left.
7. Knowledge is knowing a tomato is a fruit. Wisdom is not putting it in a fruit salad.
8. Evening news is where they begin with ‘Good Evening,’ and then proceed to tell you why it isn’t.
9. To steal ideas from one person is plagiarism. To steal from many is research.
10. A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station.
11. I thought I wanted a career. Turns out I just wanted a salary.
12. Whenever I fill out an application, in the part that says, ‘In case of emergency, notify:’ I put ‘DOCTOR.’
13. I didn’t say it was your fault, I said I was blaming you.
14. Women will never be equal to men until they can walk down the street with a bald head and a beer gut, and still think they are sexy.

15. Behind every successful man is his woman. Behind the fall of a successful man is usually another woman.
16. A clear conscience is the sign of a fuzzy memory.
17. I asked God for a bike, but I know God doesn’t work that way. So I stole a bike and asked for forgiveness.
18. You do not need a parachute to skydive. You only need a parachute to skydive again.
19. Money can’t buy happiness, but it makes misery easier to live with.
20. There’s a fine line between cuddling and holding someone down so they can’t get away.
21. I used to be indecisive. Now I’m not so sure.
22. You’re never too old to learn something stupid.
23. To be sure of hitting the target, shoot first and call whatever you hit the target.
24. Nostalgia isn’t what it used to be.
25. Change is inevitable, except from a vending machine.
26. Going to church doesn’t make you a Christian any more than standing in a garage makes you a car.
27. A diplomat is someone who tells you to go to hell in such a way that you look forward to the trip.
28. Hospitality is making your guests feel at home even when you wish they were.
29. I always take life with a grain of salt…. plus a slice of lemon, and a shot of tequila.
30. When tempted to fight fire with fire, remember that the Firemen usually use water.

“I have come to the conclusion that politics is too serious a matter to be left to politicians.” Charles de Gaulle (1890 – 1970)

“Crime does not pay as well as politics.” – Alfred E Neuman(IN CASE YOU DON’T KNOW, HE IS THE CHARACTER IN THE “MAD MAGAZINE”!)