New Server OS: Opensolaris or Nexenta?

I run a few websites, mostly based on MySQL, Rails and a little bit PHP, with currently about 5 million page impressions per month. My old server, an Athlon XP4800 with 2 GB RAM, is starting to run out of reserves, so I want to upgrade. I chose an Intel i7 920 with 8 GB RAM and 2x 750 GB disk, rented at Hetzner for € 49 per month.

I have been using Ubuntu Linux on my servers until now, and although I have been pretty happy with it in general, I want to switch to OpenSolaris for the new one.

The main reason is the ZFS file system. It handles RAID (simple mirroring or RAID-5-like), partitioning, snapshots, online resizing, all in one tool. Forget messing around with md, LVM, xfs_growfs and all the other things that you need in Linux to handle storage. Forget hardware RAID controllers, forget worrying about whether it is safe to enable write caching, or how to make sure that your SQL server syncs data properly to the disk. ZFS takes care of all that for you. And on top it offers very convenient ways to snapshot and backup data, which, despite LVM, is still a pain in Linux.

The first decision was which of the (few) OpenSolaris distributions to use.

There's OpenSolaris, currently in version 2009.06. This is the real thing directly from the core team. It comes with a packaging system that offers packages for pretty much everything that you need on a webserver (MySQL, Apache, Ruby, PHP, memcached, ...).

Then there is Nexenta. It combines the Solaris kernel with a GNU userland and the Ubuntu packaging system.

If you want to try both versions yourself, just download the ISOs and run them in VMWare or another virtual machine.

Nexenta sounds like the perfect OpenSolaris variant for someone who already knows Ubuntu, but it still looks pretty "beta", and although Nexenta is used as the basis for a fairly popular commercial NAS solution (NexentaStor), I have not found a lot of evidence of people using it for regular servers. Also the mailing lists are not very busy. So, while Nexenta is definetely something to keep an eye on, for my current task I want something proven and reliable, so I chose the "regular" OpenSolaris.

A problem with OpenSolaris is, that there is no concept of quasi-automatic security updates like in most Linux distributions, where you can just run "apt-get update && apt-get upgrade" and you get the most recent fixes. This might seem like a show-stopper; but in my case, as I will be running only my own websites on a handful of software packages, few of which are exposed to potential attackers and some of which I have to install manually anyway, it is not really a problem.