Josef “Jeff” Sipek

You have seen me publish two posts about OpenIndiana, but neither of them really says what it is and why you should use it.

The What

OpenIndiana started off as a fork of OpenSolaris. At first, its aim was to provide an alternative to Oracle’s soon-to-be-released Solaris 11, but lately its aim shifted to “an enterprise-quality OS alternative to Linux.”

OpenIndiana is much like a distro in the Linux world. It relies on the Illumos project for the kernel and basic userspace utilities (the shell, etc.). In September 2010, Illumos forked the OpenSolaris kernel and utilities, and OpenIndiana forked the surrounding userspace (the build system for all the packages that make the system usable).

The Why

It is the technology that is the reason I started using OI. Here are some of the features that either drew me in to try OI, or made me stay.

Crossbow

Crossbow was the name of the project that consisted of a major revamp of the network stack. With this revamp (which was available in OpenSolaris), you can create virtual network interfaces, vlans, bridges, switches (called etherstubs), as well as aggregate links with simple commands — quickly, and all the configuration is persistent. You can dedicate both physical and virtual links to zones (see below) to create entire network topologies within one computer. (see dladm(1M) and ipdam(1M))

Zones

These days, everyone is happily setting up virtual machines whenever they need an environment they can tweak without affecting stability of other services. Solaris zones are a great virtualization technology. They allow you to set up multiple Solaris instances (called zones) that have a separate root filesystem (much like chroot). Unlike chrooted environments, having root access in a zone does not give you unrestricted access to the kernel. Zones combined with crossbow is a great combination to consolidate separate systems onto a single Solaris host. (I am currently writing a post about using zones and crossbow on a home server/router.)

Boot Environments (BE) & IPS

Long story short, if the package manager (IPS) detects that a potentially major change is going to occur during an update (e.g., a driver or kernel upgrade), it clones the current root filesystem (easy to do thanks to ZFS) and applies the updates there. It then adds a menu entry to grub to boot into this new environment. The current environment is unchanged. At your leisure, you just reboot into the new environment. If everything works — great. If, however, things break, you can just reboot into the previous BE, and mount the new BE’s root and fix things up. This means that the only downtime the system sees is the reboot or two.

ZFS

There’s plenty of ZFS discussion elsewhere. My favorite features about it are (in no particular order): snapshots, deduplication, integrated volume management, and checksumming.

So there you have it. Sure, many of Solaris’s features are available in some shape or form on Linux, but they tend to be either horribly crippled, or if you are “lucky,” lacking sane management interface.

If you want to see what all this fuss is about, I suggest you grab the Live DVD (or Live USB) image on the download page and give it a try.