Hi Budai, When you ask "*how often the client is retrieving the Cluster Map?*" . The obvious answer to that is there is nothing 'often' in it. Whenever there is a change in the map, the monitor will inform the client. I think you need to read about the CRUSH algorithm in Ceph. Because that will explain you the map changes and data movement. While going through CRUSH, forget there is a monitor node. Just suppose there is a client machine and this client machine READ/WRITE to a cluster ( number of OSDs). Because theoretically a Ceph client can also be a monitor (not at all recommended for practical purposes). Once you have understood CRUSH, I am quite sure that will answer many of your questions. And feel free to ask about CRUSH. I would be glad to answer. BR On Wed, Jul 15, 2020 at 8:54 AM Budai Laszlo <laszlo.budai@xxxxxxxxx> wrote: > > to be more specific: if we have an RBD volume used by a client (a > hypervisor, or or mapped with rbd), we assume continuous activity on the > volume. How often will the RBD client contact the monitor to get the > current map? Are you aware of any documentation page that describes this > interaction? > > Thank you, > Laszlo > > > On 7/15/20 8:12 AM, Budai Laszlo wrote: > > Hi Nghia, > > > > in the docs (https://docs.ceph.com/docs/master/architecture/#about-pools) > there is the statement "Ceph Clients retrieve a Cluster Map from a Ceph > Monitor, and write objects to pools." My question is how often the client > is retrieving the Cluster Map? How does the client get the knowledge about > a change in the cluster? > > > > Thank you, > > Laszlo > > > > On 7/15/20 7:57 AM, Nghia Viet Tran wrote: > >> Hi Laszlo, > >> > >> Which client are you talking about? > >> > >> On 7/15/20, 11:54, "Budai Laszlo" <laszlo.budai@xxxxxxxxx> wrote: > >> > >> Hello everybody, > >> > >> I'm trying to figure out how often the ceph client is contacting > the monitors for updating its own information about the cluster map. > >> Can anyone point me to a document describing this client <-> > monitor communication? > >> > >> Thank you, > >> Laszlo > >> _______________________________________________ > >> ceph-users mailing list -- ceph-users@xxxxxxx > >> To unsubscribe send an email to ceph-users-leave@xxxxxxx > >> > > > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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