Okay, so you’re using the kernel client. What kernel version is it? I think this was one of a few known bugs there a while ago that have since been fixed. On Wed, Sep 19, 2018 at 7:24 AM Thomas Sumpter <[email protected]> wrote:
> Hi Gregory, > > > > Thanks for your reply. > > > > Yes, the file is stored on CephFS. > > Accessed using ceph client > > Everything is a basic install following the ceph-deploy guide > > > > Note sure what details would be helpful… > > The file is written to by a webserver (apache) > > The file is accessed by the webserver on request of some specific data > within the file. The webserver will fetch the file from the local OS i.e. > file://some_file, which in turn is fetched from the cephfs. > > An observation, if I tell the webserver to make a web request to itself to > fetch the file (http://localhost/etc), then I don’t have the problem. > > > > # mount | grep ceph > > mon-1:6789,mon-2:6789,mon-3:6789:/ on /mnt/ceph type ceph > (rw,noatime,name=admin,secret=<hidden>,acl) > > > > # rpm -qa | grep ceph > > libcephfs2-13.2.1-0.el7.x86_64 > > python-cephfs-13.2.1-0.el7.x86_64 > > ceph-common-13.2.1-0.el7.x86_64 > > > > # ceph --version > > ceph version 13.2.1 (5533ecdc0fda920179d7ad84e0aa65a127b20d77) mimic > (stable) > > > > Regards, > > Tom > > > > *From:* Gregory Farnum <[email protected]> > *Sent:* Wednesday, September 19, 2018 4:04 PM > *To:* Thomas Sumpter <[email protected]> > *Cc:* [email protected] > *Subject:* Re: [ceph-users] Delay Between Writing Data and that Data > being available for reading? > > > > You're going to need to tell us *exactly* what you're doing. I presume > this uses CephFS somehow? Are you accessing via NFS or something? Using > what client versions? > > > > CephFS certainly isn't supposed to allow this, and I don't think there are > any currently known bugs which could leak it. But there are lots of things > you can stack on top of it which won't provide the same guarantees. > > > > On Wed, Sep 19, 2018 at 6:45 AM Thomas Sumpter <[email protected]> > wrote: > > Hello, > > > > We have Mimic version 13.2.1 using Bluestore. OSDs are using NVMe disks > for data storage (in AWS). > > Four OSDs are active in replicated mode. > > Further information on request, since there are so many config options I > am not sure where to focus my attention yet. Assume we have default > options. > > > > We have a scenario where one file is continuously been written to and read > from. > > Very occasionally the write operation is completed but then the subsequent > read op on that file does not contain this new data for a brief period. > > Does anyone know a reason for the delay between write operations being > completed and the new data that was written to be present in the file? > > It is not very easily reproducible, but possible with fast scripted > attempts. We do not have this problem when using other filesystems. > > > > Note: there is one client writing data and 2 clients reading data to/from > this file. > > > > Many Thanks! > > Tom > > _______________________________________________ > ceph-users mailing list > [email protected] > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >
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