How can I get quicklook to ignore network volumes? How can I modify com.apple.qtkitserver.sb to ignore a certain network volume?
For example, I don't want quicklook to build previews of graphic assets that are on a server. When I access a netatalk share with hundreds of jpg's in a folder, fs_usage shows a ton of transactions like this:

09:43:15.675208  getattrlist                            /Applications/Preview.app                                                                                                                                             0.000007   Finder.2001210
09:43:15.675276  getattrlist                            /Volumes/server/path/file.jpg                  0.000010   Finder.2001210
09:43:15.675735  open              F=38       (R_____)  /Volumes/server/path/file.jpg &gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;    0.000458 W Finder.2001210
09:43:15.675738  fstat64           F=38                                                                                                                                                                                       0.000002   Finder.2001210
09:43:15.675745  pread             F=38   B=0x24       O=0x00000000                                                                                                                                                           0.000003   Finder.2001210
09:43:15.675748  pread             F=38   B=0x62       O=0x00030235                                                                                                                                                           0.000002   Finder.2001210
09:43:15.676384  close             F=38                                                                                                                                                                                       0.000634 W Finder.2001210


Which I am guessing is quicklook building thumbnails and previews of the files contained therein. This is slowing finder down to a crawl until the transactions complete.

I tried adding the rule:

(deny file-read
      (subpath "/Volumes/Volumename"))


That did not seem to have any effect.
It is not quicklook that is trying to generate previews on its own, it is Finder that triggers it when you access that (and any other) folder on any mounted drive.

When in the folder, open Finder / View / Show View Options (shortcut Cmd+J), deselect Show Icon Preview and click Use as Defaults. That information is stored in the .DS_Store file in each folder.