Hi, for RHEL5, I'm not sure be barriers supported is maybe not implemented in virtio devices,lvm,dm raid and some filesystem, depend of the kernel version. Not sure what is backported in rhel5 kernel see http://monolight.cc/2011/06/barriers-caches-filesystems/ ----- Mail original ----- De: "Yufang Zhang" <yufang521247 at gmail.com> ?: ceph-users at lists.ceph.com Envoy?: Vendredi 22 Ao?t 2014 13:05:02 Objet: [ceph-users] Is it safe to enable rbd cache with qemu? Hi guys, Apologize if this question has been asked before. I'd like to know if it is safe to enable rbd cache with qemu (cache mode set as writeback) in production? Currently, there are 4 types of guest os supported in our production: REHL5, RHEL6, Win2k3, Win2k8. Our host is RHEL6.2 on which qemu supports ' barrier-passing'. Thus we have confident that RHEL6 guests(with barrier enabled by default ) could work well with rbd cache enabled. But as for REHL5, Win2k3 and Win2k8, I am not sure if it is 100% safe on scenarios such as guest crash, host crash or power loss. Could anybody give some suggestion? Really appreciate your help. Yufang _______________________________________________ ceph-users mailing list ceph-users at lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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