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.