Hello, On Wed, 18 May 2016 13:57:59 +0200 Dietmar Rieder wrote: > Dear Ceph users, > > I've a question regarding the memory recommendations for an OSD node. > > The official Ceph hardware recommendations say that an OSD node should > have 1GB Ram / TB OSD [1] > > The "Reference Architecture" whitpaper from Red Hat & Supermicro says > that "typically" 2GB of memory per OSD on a OSD node is used. [2] > This question has been asked and answered here countless times. Maybe something a bit more detailed ought to be placed in the first location, or simply a reference to the 2nd one. But then again, that would detract from the RH added value. > According to the recommendation in [1] an OSD node with 24x 8TB OSD > disks is "underpowered " when it is equipped with 128GB of RAM. > However, following the "recommendation" in [2] 128GB should be plenty > enough. > It's fine per se, the OSD processes will not consume all of that even in extreme situations. Very large OSDs and high density storage nodes have other issues and challenges, tuning and memory wise. There are several threads about these recently, including today. > I'm wondering which of the two is good enough for a Ceph cluster with 10 > nodes using EC (6+3) > I would spend more time pondering about the CPU power of these machines (EC need more) and what cache tier to get. That is, if performance is a requirement in your use case. Christian > Thanks for any comment > Dietmar > > [1] http://docs.ceph.com/docs/jewel/start/hardware-recommendations/ > [2] > https://www.redhat.com/en/files/resources/en-rhst-cephstorage-supermicro-INC0270868_v2_0715.pdf > -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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