Hi there, I am running KVM virtual machines and with libvirt, I am able to attach volumes to the running VM instance. However, it turned out that different latest Linux distributions have different results on getting the volume live. I've tried Fedora Core 12, Ubuntu 9.10 and CentOS 5.4. Only FC12 is able to see the attached volume right away. Ubuntu and CentOS need to be rebooted to see the newly attached volumes. In my understanding, all three distributions are running udev now and I think udev is what is responsible for hot plug devices. Am I right? I suspected this is caused by the udev kernel configurations. Therefore, I obtained the FC12 kernel source and build them and installed the newly built kernel onto my Ubuntu 9.10 and CentOS 5.4 VMs and viola, they both work with live attached volumes seen immediately, no need for reboot. So it is confirmed it is the kernel that matters here, instead of user space software. However, I googled around and found that to enable udev, we need the following kernel options: 21 CONFIG_HOTPLUG=y 22 CONFIG_UEVENT_HELPER_PATH="" 23 CONFIG_NET=y 24 CONFIG_UNIX=y 25 CONFIG_SYSFS=y 26 CONFIG_SYSFS_DEPRECATED*=n 27 CONFIG_PROC_FS=y 28 CONFIG_TMPFS=y 29 CONFIG_INOTIFY_USER=y 30 CONFIG_SIGNALFD=y Interestingly, all 3 original kernels for the 3 distributions have the above kernel options enabled. Apparently, they are not the deciding factors for the volume hot-plug for work or fail. I am sending this email to ask what other kernel options I have to pay attention to. In short, if I am going to change the Ubuntu or CentOS kernels to support volume hot plug, where do I change? Thank you very much. Shi -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
