UKOUG / LOSUG Jan 2015

Or, Down the Rabbit Hole.

I checked the archives and the last event I went to was in May 2012. Everything was exactly the same as it was then, although my extended absence just heightened to me how surreal the whole event is.

I don’t mean that in a bad way at all. Quite the opposite. Peter Tribble gave an interesting talk entitled “Adventures with illumos”. Myself and the other middle aged geeks were treated with another journey down memory lane where I heard words long absent from my ears like “Sun”, “Solaris” and “CDE”.

The irony is, a lot of the technology is new, and as Peter ably demonstrated is actively being worked on. What made it surreal is how far divorced it all is from the “real” i.e. commercial world, especially if you have been exclusively in that environment for a few years, dealing with big vendors, clients and “The Cloud”.

There’s something very “British”, and heartening about how, hobbyists (can’t think of a better description) dedicate their time to preserve and develop something that is of value because they (we) love the technology: the effort and creativity that is embedded in it and the respect for the people who have worked on it before. People are not doing this to become the next dot com with A,B and C round funding. They’re doing it because they love it.

As time goes by and the rise of the machines continues, this community could form the core of a whole new field. In the compressed timescales of IT, the rate of change and the knowledge that could be lost is a real risk. Britain is very good at preserving heritage; in IT terms, Bletchley Park is the obvious example that springs to mind and you can find sites like http://www.ourcomputerheritage.org/. These however, are mainly concerned with hardware; hardware that can be identified with a specific country.

Code is different. It is global. It is like DNA, literally “code”. It contains lots of redundancy and continually evolves. How do we preserve it? Should we preserve it? Is anyone else writing this story down? Who is carrying on the work of Peter Salus and his history of Unix http://www.amazon.com/Quarter-Century-UNIX-Peter-Salus/dp/0201547775?

Great to have a dose of un-commerciality once in a while.

UKOUG / LOSUG May 2012

Late, but as promised, a quick blog on Dr. Clive King’s presentation to the OpenSolaris User Group in September.

Another great talk which will particularly stick in my mind for the anecdote about the customer who bought larger and larger systems to solve performance problems and ultimately found out that RAM was being artificially limited by a system setting. Ouch. That came from Clive’s tip #1: don’t copy /etc/system settings!

I noted down 10 tips in total and got links to other good blogs like Gerry Haskin’s blog.

By the time the room got hot and stuffy, we were into the realms of chip performance, large pages and MMU traps so we had covered a large spectrum.

If I do any Solaris performance tuning in the future, this talk will certainly be my starting point.

LOSUG – UKOUG February

I missed a few months of LOSUG due to one thing and another so was looking forward to Andrew Watkin’s talk on ‘Solaris 11 Automated Installer Walkthrough’. As usual, an engaging and interesting talk! I hadn’t even realised that Jumpstart was dead, as it quickly transpired in the talk. Jumpstart, Jet, building servers in general was my ‘specialist subject’ for a large part of my Unix sysadmin career. It made me realise how out-of-date my Solaris skills were becoming, not having used it on a daily basis for, well a few years. The last major piece of Solaris work I did was the build engineering for a Solaris 10 rollout and that was all done with Jet and flars.

This new ‘AI’ system in Solaris 11 does seem like work still in progress, although it has been around since 0609. ‘What about images?’, I asked, only to find that no equivalent of flar’s existed in Solaris 11. I really must install some Solaris 11 on my home lab!

P.S. I downloaded the llive DVD and started an install from it. The first stage of the install is transferring cpio files. Perhaps there’s life in the old flar yet!

UKOUG/LOSUG November

Recently I’ve been very busy experimenting with vCloud Director in the office lab. It’s a complex beastie and many thanks to Duncan Epping for his excellent turorials. When I get more experience, I may blog on it but as I have a dozen things to do on my ever growing list, it seems unlikely. One quick note to self though: the strange error I got about a host already being controlled was due to agent confusion and I had to run vslad-uninstall.sh and re-install to fix.

Now, on to the subject. Alastair Lumsden introduced this months UKOUG/LOSUG speakers Tom Kranz and Peter Tribble attended by the usual suspects in the audience. Tom talked about “Exploring Solaris Auto Registration” – that part of Solaris in Update 9 which sends all your machine details to Oracle over the internet, oh yes. Now in 99% of cases you don’t want it to do this so he explained how to disable it and some of the commands involved: stclient, stlisten, stdiscover. All worth reading up on for the professional Solaris Admin.

Peter Tribble’s talk was titled “Sar – past present and future” and, lets face it, “past” is the key word here. No-one was arguing with that point of view but Peter showed a good, simple idea to allow people to keep historical data and use it to assist in problem diagnosis and as a source of graphs for management. Keeping historical data was/is one of sar’s useful aspects. Peter simply keeps kstat -p output and stores it in compressed format for future use. The storage required is not that large and you can quite easily keep a couple of years worth. He has written some tools to scan the compessed logs and mimic the output of stat commands so you can see what “mpstat 10” would have produced at midnight on February 20th last year, if you want.

Perhaps we’ll get a talk on sar’s older brother, process accounting one month 🙂 No, please, just joking.

Next month Alastair is planning workshops, running from late afternoon which could be interesting and in January Jim Mauro is in the country promoting the new dtrace book and we can look forward to a talk from him!

LOSUG September

I attended the Oracle LOSUG meeting on September 15th to hear a talk from Phil Kirk on Zones and Crossbow.

I also took the opportunity to meet Alasdair Lumsden (who has set up openindiana).

I scribbled down a few notes to help jog my memory.

HISTORY

  • Zones were never meant to be like VMs. They were designed as a process container.
  • Zones have a shared I/P stack and routing.
  • There is (typically) a separate I/P alias per zone.
  • IPMP works.
  • Config is done from the global zone.
  • IPfilter works (v4).
  • DHCP, IPsec, raw sockets don’t work.

Some problems with zones:

  • Non-global routing is affected by global routing table. (Some examples).
  • Using a null route is often used to add a gateway entry but this is where global routing table changes can break zones.
  • Default routes are selected round-robin.
  • defrouter option in the zone config just does a route add (nothing clever in the kernel).
  • inter-zone traffic can be forced to go over the wire. Normally it would go via loopback for efficiency but some sites require audit/logging of traffic.

NOW

  • Each zone gets its own I/P stack.
  • Config is done in the zone.
  • Lots of zones need lots of NICs.
  • Can mix shared and exclusive stacks.

CROSSBOW:

  • Virtualisation at the data (mac addr) level. vNICs.
  • vNIC gives b/w resource management (dladm).
  • vlans are supported in Crossbow.
  • P.S. What happened to my complimentary UKOUG membership?

LOSUG

That’s the London Open Solaris User Group. I went along last night mainly for the talk on Virtualbox internals. Unfortunately the speaker had to cancel at short notice. Have to wait until that comes round again.  I should add Virtualbox to my list of things to experiment with. I tried it a year ago on my notebook and it worked well.

On the plus side we got a great talk from Robert Milkowski on his contribution to ZFS in Opensolaris. It is best explained by him in his blog.

The general idea is that in some circumstances it is beneficial to be able to “over-ride” the application specified behaviour when it comes to writes: synchronous or asynchronous. His enhancement adds features to allow this to be done. At the flick of a switch you can make all writes asynchronous while fooling all apps into thinking they are synchronous. This can give you a 2 order of magnitude speed up! Furthermore the switch can be set at any level, including individual filesystems or zvols.

It should, of course, be used with some appreciation of the risks. In many cases the risks are acceptable as ZFS integrity is always guaranteed, even if data integrity is not. Back in the day similar functionality existed for UFS filesystems but it was very easy to completely trash a UFS filesystem.

It was also inspiring to see with what relative ease you can contribute to Open Solaris. Ahhhh, for more time.

Chatting to some folks afterwards I mentioned I was really in to virtualisation. Reasonably, I was asked what was the best virtualisation software to use on Debian for running a windows program. I think Virtualbox would do nicely but cannot speak from experience. Just goes to show how many combinations of O/S and hypervisor there are out there to get familiar with.