Hi, I am considering deploying Ceph as the volume backend for our Openstack cloud service. After reviewing the documents available on the Internet, I am still confusing with several things. 1. Architecture/Implementation questions: What are the functionalities of kernel-rbd, kernel client, kernel object exactly? How the different parts of Ceph interact with each other, e.g. what is the data path of librados/librbd requests going into OSD daemon? 2. QEMU performance: It says the QEMU uses librbd to avoid the overhead of kernel object. What does this mean? With the answer of question 1, I can probably understand this one. Do you have any data about the performance difference between Ceph and Sheepdog? 3. OS recommendation: The OS recommendation page: http://ceph.com/docs/master/install/os-recommendations/#bobtail-0-56 says CentOS 6.3 has a default kernel with old kernel client. CentOS 6.3 is our production environment. I am wondering if we only make use of the Ceph block storage feature, does this old kernel client influence the stability of production? Do you suggest we upgrade from the default kernel of CentOS 6.3? I am concerning this will hurt the stability of CentOS. Thank you very much for anwsering my questions. I really appreciate. Regards, Peter -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
