We’ve had several more SIS questions come in. Here they are, along with their answers:

How does SIS work with quotas?

If a file is SIS linked after applying a quota, then only the size of the reparse point of that file is counted towards the quota. If a file is SIS linked before applying a quota, then the actual size of the file is counted towards the quota. If a directory quota is preventing SIS from bringing a changed file back from the SIS Common Store, part of the file will be brought back. The remaining part will stay in the SIS Common Store. SIS will retry this operation every time the file is changed.

What happens if the SIS "database" get corrupted?

With regards to corrupted database, it depends on exactly what you mean.  If you mean the jet database that the groveler uses, it will simply start over.  If you mean the common store in general, such as files being deleted or corrupted in other ways, that will manifest itself as corrupted link files.  There is no way to fix that other than restoring.

How does this work with encrypted files?

SIS will not allow EFS encrypted files to become SIS links.  If EFS encryption is attempted on a SIS link, SIS will copy the file out before allowing EFS to work on the file.

 --Jill (and thanks to Claus, Darren, and Senthil for answering these questions)