I hope I can post here a general question/comment regarding distributions. Because I see a lot of stability issues passing by here. Why are people choosing an ubuntu distribution to run in production? Mostly I get an answer like they are accustomed to using it. But is the OS not just a tool? And you have to choose the correct tool for the job (and then learn to use it)? When I chose centos it was because it is close related to redhat, and for critical situations I would choose or switch to the rhel license. There over 10k people working at redhat to produce a stable os. I am very pleased with the level of knowledge here and what redhat is doing general. I just have to finish with; You people working on Ceph are doing a great job and are working on a great project! -----Original Message----- From: Bogdan SOLGA [mailto:bogdan.solga@xxxxxxxxx] Sent: vrijdag 27 oktober 2017 18:33 To: ceph-users Cc: Stephen Oliver; Ákos Nagy Subject: Kernel version recommendation Hello, everyone! We have recently upgraded our Ceph pool to the latest Luminous release. On one of the servers that we used as Ceph clients we had several freeze issues, which we empirically linked to the concurrent usage of some I/O operations - writing in an LXD container (backed by Ceph) while there was an ongoing PG rebalancing. We searched for the issue's cause through the logs, but we haven't found anything useful. At that time the server was running Ubuntu 16 with a 4.5 kernel. We thought an upgrade to the latest HWE kernel (4.10) would help, but we had the same freezing issues after the kernel upgrade. Of course, we're aware that we have tried to fix / avoid the issue without understanding it's cause. After seeing the OS recommendations from the Ceph page <https://github.com/ceph/ceph/blob/master/doc/start/os-recommendations.rst> , we reinstalled the server (and got the 4.4 kernel), we ran into a feature set mismatch issue when mounting a RBD image. We concluded <http://cephnotes.ksperis.com/blog/2014/01/21/feature-set-mismatch-error-on-ceph-kernel-client> that the feature set requires a kernel > 4.5. Our question - how would you recommend us to proceed? Shall we re-upgrade to the HWE kernel (4.10) or to another kernel version? Would you recommend an alternative solution? Thank you very much, we're looking forward for your advice. Kind regards, Bogdan _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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