2017-03-02 23:25 GMT+08:00 Ilya Dryomov <idryomov@xxxxxxxxx>: > On Thu, Mar 2, 2017 at 1:06 AM, Sage Weil <sage@xxxxxxxxxxxx> wrote: >> On Thu, 2 Mar 2017, Xiaoxi Chen wrote: >>> >Still applies. Just create a Round Robin DNS record. The clients will >>> obtain a new monmap while they are connected to the cluster. >>> It works to some extent, but causing issue for "mount -a". We have such >>> deployment nowaday, a GTM(kinds of dns) record created with all MDS ips and >>> it works fine in terms of failover/ mount. >>> >>> But, user usually automation such mount by fstab and even, "mount -a " are >>> periodically called. With such DNS approach above, they will get mount point >>> busy message every time. Just due to mount.ceph resolve the DNS name to >>> another IP, and kernel client was feeling like you are trying to attach >>> another fs... >> >> The kernel client is (should be!) smart enough to tell that it is the same >> mount point and will share the superblock. If you see a problem here it's >> a bug. > > I think -EBUSY actually points out that the sharing code is working. > > The DNS name in fstab doesn't match the IPs it resolves to, so "mount > -a" attempts to mount. The kernel client tells that it's the same fs > and returns the existing super to the VFS. The VFS refuses the same > super on the same mount point... True, root@lvspuppetmaster-ng2-1209253:/mnt# mount -a mount error 16 = Device or resource busy Do we have any chane to make dynamic works(i.e suppress the -EBUSY for this case) for old kernel? > > We should look into enabling the in-kernel DNS resolver. Thanks for explaination, looking forward :) > > Thanks, > > Ilya _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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