I have been using KVM for virtualization since SLES10 and have moved up to SLES11SP4 with no problems. Over a period of time I have experimented with moving to SLES12, iterations 1,2, and now 3. Each time I carry out the operation, I find that the server may hang at times for periods of up to one minute, before everything starts working again. I have tried this on SLES1,2 and now 3 but always get the same results. Also tried this out on a second server with exactly the same thing happening. The servers are running an 8 core AMD processor with 32 GB ram, and will work for months under SLES11 with now problems or requirement to reboot anything.
Does anyone have any ideas or pointers to the problems I am getting with SLES12, as SLES10 and 11 all work fine!