I'm hoping you don't see this as a thread hijack, but I thought my problem was very similar to yours, and since I found this thread via google search, others may have as well.
I've had nothing but issues since installing 6.2 SP1:
- The first issue I encountered was that the 2nd server in my pool bombed out after the patch install (yes, I did the master first) and wouldn't connect to the pool because of the "no interface configured" error. I followed this guide to fix it without having to reinstall: http://www.e-rave.nl/xenserver-6-how-to-fix-no-interface-configured-after-update-or-hotfix
- The next issue is that all my servers (Debian, Win2k8, Win2k12, etc...) are horrendously slow. Just to start the process of updating the XenTools install on my Win2k8 domain controllers took nearly 30 minutes.
- Which leads to the tools install. The install on the Win2k8 DC stopped after an hour, with a hang on the driver install portion. I tried forcing a reboot, but it took 30-40 minutes to get to the desktop. Instead of saying the tools were outdated, it said they were not installed. I am now in the process of restoring to the snapshot I took right before starting the tool install (thank God I did that), but it's been nearly 30 minutes since I selected "restore", and it still hasn't booted up yet.
- The last problem is that I keep losing the connection to the pool master every 10 minutes or so... sometimes, every 1-2 minutes. In XenCenter, I've just had to right-click and hit connect again, but I've never had this issue before.
If I could get both DCs up and running, I would evacuate them to the 2nd server (I can only imagine how long that is going to take) and reboot the pool master. That is where I'm at right now. If anyone can help, I would really appreciate it.
If I should start a new thread, I can do that as well. It just seemed very related to the OP.
** EDIT **
At this point, I'm considering doing a hard reboot of both hosts. The VMs are so slow right now, they're essentially unusable. Not sure what else to do. It has been over 45 minutes, and the restored-from-snap (pre-SP1 tools install) still has not fully booted up.
** EDIT 2 **
After a hard reboot of both XenServers an hour ago, things seem to be better. The VMs are still slow, but they are at least usable now. I am still dealing with an Exchange server that didn't like the hard shutdown very well, so I'm restoring it from a snap.
I am still very hesitant to install the updated XenTools. I'm hoping it goes better the next try, which will probably be tonight when everyone is sleeping.