I've got a webserver running on Slack10, and I've been sizing up Solaris for a little while. Does Solaris make a good webserver. The OS on my server is in a bad state of disrepair. A buddy of mine is a Solaris nut, but I don't want to talk to him about Solaris unless I have too. (I'd be there all day.)

I'm going to replace my server's OS anyways, should I look into Solaris more?

Solaris can sure shine as a webserver ..., especially with its version 10 new TCP/IP's stack and NCA (network cache and accelerator).

totally agreed.

Would it be worth switching from Linux? I'm going to dump my OS and either reinstall it or replace it anyway. It couldn't hurt to try, right? Should I use the downloadable Solaris9 at Sun's site, or should I got have a chat with that buddy of mine to see about some Solaris10?

EDIT: I don't mean, "he has Solaris10", I mean, "should I ask him about it more?"

There are some parameters you should consider before switching to Solaris.
- is your hardware supported ? (some network cards and sata controllers are still missing support for example, and using Linux drivers is not an option, due to GPL limitations)
- Solaris and Linux are close, but not identical, so you will need to learn the differences, especially in the admin area.
- Which one of Solaris 9 or 10 is the best for your needs ? If security is a concern, I would suggest you to wait for the official Solaris 10 (end of next January) and not the beta currently available. Then install your web server in a zone (secure container).

If you have enough disk space, a good option would be to install both Linux and Solaris in a dual boot configuration, with the web server document root on a shared partition.
That would give you a ready to run fail-over solution should you break one of the O/Ses.

All of the hardware in my webserver is as generic as can be. I don't have a sound card in there, and it uses an onboard VGA card. The system is IDE based, and will not use SATA, SCSI, or USB connected drives.

Security isn't really a concern. I mean, I would prefer nobody break into my server and fubar everything, but my server is Ghosted every other day, so the worst they could do is destroy the last day or so of data.

As far as differences between Linux and Solaris, what are we talking? Do we mean small things like "the backspace key is a no-no", or monumental things like "everything is completely changed"?

Not everything is completely changed, but little things are different, for instance, hard drives are named differently, some of the commands have differen options (because they're not the GNU versions, though you can install the GNU stuff), the package management is somewhat different (though you ave an advantage coming from Slack, since it's pretty close to tgzs), etc. A seasoned Linux admin should have little trouble switching to Solaris, but you will have to take a couple of days to get familiar with all of the little things.

I'd say somewhere in the middle ...
There are often major differences between one Linux distro and another and even more between Linux and BSD, so if you are used to deal with these situations, you are more prepared.
This is including the backspace/delete leadership war that I always fix, both with Solaris and Linux, with an "stty erase ^H"

On the other hand, Gnu/Linux with the time has become more standard compliant, more SystemV-ish and has adopted many Posix and Solaris features, so some differences are fading.
Solaris too is adopting some free alternatives of its own closed source implementations (Xorg vs Xsun, JDS (Gnome/gtk) vs CDE/motif) and some major freeware are now part of the standard Solaris installation (apache, perl, samba, ghostscript, openSSH, ...)

All what is based on open source software, like bind, sendmail, Xorg, apache, gcc, gnome, all gnu utilities, kde, bash, samba, cups, netscape/mozilla/firefox/thunderbird, staroffice/openoffice.org, the gimp, tomcat, netbeans, eclipse and a million other freewares are virtually the same, with just some slight difference in the installation directories (/usr/local is not a directory where, under SVR4/Solaris rules, you are allowed to install unbundled software), and very unfrequently in features (like smbmount which is only supported with Linux).

Java is hopefully behaving the same on both.

The most differences found are in the administrative area: installation, network settings, file-systems, device, /proc, system interfaces, and packaging (as btmiller pointed) are from close to very different, so be prepared to read manual pages and goggle a little to understand how to configure and manage the system.

Some features are only present with Solaris (resource management, zones, dtrace, role based access control, kernel dubugger, crash dumps, ...) and some features are present in Linux and not there with Solaris (wider H/W support, more filesystems support, virtual consoles, ...)

One major difference that Solaris 10 is bringing is the new service management system (greenline), that used to be very similar with previous versions (/etc/rc*.d/Sxxx ...) and is now managed a far better way.

A couple of days is probably optimistic to be familiar with all of this, but it certainly worth the effort.