If I create a file in qtree1, and then try to create a hard link in tree2 for the file, it will complain "Invalid cross-device link." So it seems to me a qtree is like a volume having its own file system. In other words, say in qtree1 a file has inode 11111, it's possible in qtree2 there a file also having inode 11111. Is it correct?
I know hard links should be avoided in general but unfortunately the data set i am dealing with already have alot of hard links and I need to migrate them from isilon to NetApp.
thanks for the info. The problem is I am migrating data from Isilon and it has alot of hard links. I have to create qtrees to keep the quota setups similar to the Isilon so there are many qtrees under the volume. When I copy files from Isilon to NetApp, it fails with "invalid cross-device link" error as you described because the hard links go across qtrees. I doubt there is a way to work around this. Any suggestions?