Questions about the .sfs file

[ArmchairGravy]

I took a gander at persistant.sfs last night and ended up with a couple of questions I'm hoping the community can answer.

First, since this is where the ships/flags/debris is tracked, and the more ships/flags/debris you have the slower the game gets, I'm assuming that the more Vessels are in the .sfs file the worse the game performs. Does the part count on the Vessels play a part in this as well? Or does part count only come into play when the ship is active/within range of an active ship? For example, would 50 ships with 100 parts each degrade the game the same way 50 flags would?

Second, would saving out copies of just the persistant.sfs file act as a way to restore to a previous point? Or do I need the whole folder? My ships/sub-assemblies are pretty static at this point, but I'm trying new stuff with them that has a high chance of going pear-shape and stranding/killing a bunch of my green friends. If I could just save the .sfs without needing the whole folder it'd save me some precious disk space.

Edited March 8, 2014 by ArmchairGravy

[Jimbimbibble]

The physics engine only simulates objects within 2.3km, so having a lot of ships doesn't really cause lag. Anything outside that radius is treated as a single point on rails, which takes very little CPU time. Your idea about using the persistent file as a backup works exactly as you said. The ships folder is not needed to do this because the persistence file contains all the information about active ships. You just wouldn't have anything in the VAB. You can even trade the file with people to do a multiplayer-like thing. Just make sure that you have all the required part files when you load or it will delete any ships that have missing parts.

[DonLorenzo]

Having many ships/debris in your .sfs definitely does decrease performance. I start to notice it around 150 distinct entities and it becomes bothersome around 500-600. Obviously YMMV depending on your system, kinds of debris (I've not figured out how it works precisely. Hundreds of debris around kerbin will still give me silky smooth performance around any other celestial, and it's especially the map view that suffers) and maybe other variables.

[Yasmy]

I run a little script to watch for changes in quicksave.sfs and persistant.sfs,

and automatically commit the changes to a repository.

It basically runs 'git commit -m "autosaving" in a loop at regular intervals.

This way I can scroll back in time to pretty much any quicksave or persistence update.

Very handy.

Would highly recommend.

[Silverchain]

Lots of flights and debris decreases performance. Part count on those objects doesn't as far as I know.

[Starstrider42]

Part count will increase loading time (as you've probably noticed, it takes a LOT of text to describe every setting on every module), but I'm not aware of any in-game effect except on active vessels.

[ArmchairGravy]

Thanks, folks!