Update: Using mount (read-only) and unmount commands in a script that loops continuously, we are able to see near instantaneous file modifications (less than 0.5 sec) performed on a Win7 live guest. We have to use the sync.exe utility (technet.microsoft.com/en-us/sysinternals/bb897438.aspx), otherwise changes are not visible for 10-20 sec. We tested sync.exe with our libguestfs test program (using various methods, including rsync_out, and w/wo sync on Linux side), but we're still not able to see live guest file changes until we relaunch the image. Any advice on how to get around the relaunch requirement (which takes 3-5 sec due to loading the appliance Linux kernel), would be greatly appreciated. There are many reasons why using libguestfs is a better solution for us in the long run. Thanks. -Jeff ---------------- Original Message --------------- Subject: Re: [Libguestfs] getting guestfs_rsync_out to work From: "Jeff Brower" <jbrower(a)signalogic.com&gt; Date: Mon, February 9, 2015 3:39 pm To: "Richard W.M. Jones" <rjones(a)redhat.com&gt; Cc: libguestfs(a)redhat.com ------------------------------------------------- Richard- takes (if we could get into 1 to 10 msec range it would be ok). to initialize itself. Even if you use the User-mode Linux backend (which just runs vmlinux as a userspace process) you'll experience approximately the same overhead. Ok got it. Thanks again for your reply. We tried guestfs_drop_caches() as follows: while(1) { guestfs_mount(g, "/dev/sda2", "/"); printf("%s\n", guestfs_cat(g, "/HostShared/temp.txt")); guestfs_umount(g, "/"); guestfs_drop_caches(g, 3); usleep(1000*1000); } and still we cannot see changes made to temp.txt (from inside the Win7 guest VM) while this loop continues to run on the host Linux. We still have to re-launch the image to see changes. In general, it would be great if the "kernel load" and "disk refresh / sync" functions in guestfs_launch() could be separated. If there was a way to do read-only file sharing, a very limited subset of what virtFs/9p can do, that would be great for Win guests. -Jeff