Additional suggestions for server admins. I'll admit I have spotty internet and don't currently play multiplayer, but all the same these things should keep the server running faster.

1. Unpack the starbound assets
2. Install PNGGaunlet. Set the settings to replace the original files. I have the passes setting maxed, etc.
3. Drag the whole directory(where ever you extracted packed.pak to) onto PNGGauntlet. It will find all PNG files in all subdirectories.
4. Hit optimize. This will take considerable time. But you're cutting the non-audio asset size in half and with it the load/reload/reload/reload/reload/reload/reload/reload time. Yes that's the joke... Starbound handles asset loading badly. Anyhow I personally did it within a virtual machine so I could easily limit it to use only 2 CPU cores and leave my computer otherwise quite responsive. It could have been done faster had I not done that. Make your own choices here.
5. Repack the results and use that file to replace the normal packed.pak
6. If you have manually installed mods, you might consider doing the same to the mods. Don't worry about my mods because I do this before releasing/updating them.
7. I have no flipping idea if it is okay to distribute this version of packed.pak. My instincts say... no. They allow doing so on a small scale, but this... I dunno maybe ask the devs. It should still be helpful that you have this version on the server.

Using symbolic links to the workshop directory from /mods/ might be a better option than manual download/update. You can do that per-mod or...
1. Close down Steam.
2. Move everything from the steamapps/workshop/content/211820/ folder directly to the /mods/folder
3. Delete /211820/
4. Make a symbolic link to replace /211820/ but that actually points to starbound/mods/ (the directions vary by OS, but you ARE on the internet so Google/Youtube that if you don't know how).
5. Restart Steam. It should keep the mods up-to-date for you. Especially have it set to auto-updae them for you and put Starbound as a high priority. When Steam attempts to read from or write to /211820/ it will actually affect /starbound/mods/ instead and Steam shouldn't know any better.
6. Don't lauch Starbound from Steam. Make shortcuts to the executables. Otherwise it would try to double-up on workshop mods.

I might also suggest cloning to and running Starbound from a RAMdisk for much better performance. There are free RAMdisk programs out there that aren't hard to use if you have a little extra RAM. This will greatly compensate for the terrible asset handling that Starbound is notorious for(and the source of much lag). Even if you have an SSD, it cannot compare to a RAMdisk for speed, trust me.

You might still consider making a symbolic link from the Ramdisk that points to the /storage/ on the physical disk. That's slower, yes. But RAMdisks get cleared every boot. You have to copy stuff to them each time, and therefore you probably don't want your save files there unless you have a background script periodically keeping the HD folder up to date.

Probably you also have your pagefile disabled, right? If you have enough RAM, running a pagefile is stupid. Default for Windows... but stupid. This is the total opposite of the RAMdisk. The best way to slow things down, and bring SSDs to their death much faster.