What are OpenSolaris/Solaris strengths on server hardware?

Solution 1:

I would say two of the big advantages to Solaris are ZFS (http://en.wikipedia.org/wiki/ZFS) which is a 128-bit filesystem who's awesomeness I could not begin to describe in a few paragraphs, and DTrace (http://en.wikipedia.org/wiki/DTrace), which allows for kernel level troubleshooting/tuning of production systems in realtime.

Edit: Sun has a "benefits of running Solaris 10" document available here: http://www.sun.com/bigadmin/features/articles/s10_dsee_benefits.pdf

Solution 2:

Besides the marquee features (ZFS, Zones, DTrace) people mentioned above, (Open)Solaris also has great observability and management tools. Some things that I like:

• prstat - sort of like top but can view tons of stats based on per-process or per thread including breakdown of CPU time by many different categories (sleeping, locks, waiting on CPU, etc)
• coreadm - easily administer how core files are named and managed
• plockstat - view userland lock statistics for a process
• lockstat - view kernel locks
• FMA - fault management architecture handles HW failures well and has good reporting
• privileges - hand out "bite sized" pieces of root privileges to accounts that need it

Also, the new 2009.06 OpenSolaris release has:

• Excellent network virtualization support (vanity interface naming, virtual NICs, easy rate limiting)
• Multi-protocol (iSCSI, FC) storage target support

One thing that has long frustrated me with Solaris is the antiquated packaging/patching system. This is being fixed in OpensSolaris with a new package management system. I think there is still some work to do, but it is coming along fairly well.