Ceph uses CRUSH (http://ceph.com/docs/master/rados/operations/crush-map/) to determine object placement. The default generated crush maps are sane, in that they will put replicas in placement groups into separate failure domains. You do not need to worry about this simple failure case, but you should consider the network and disk i/o consequences of re-replicating large amounts of data. Sean ________________________________________ From: ceph-users [ceph-users-bounces@xxxxxxxxxxxxxx] on behalf of LaBarre, James (CTR) A6IT [James.LaBarre at Cigna.com] Sent: Thursday, August 21, 2014 9:17 AM To: ceph-users at ceph.com Subject: Question on OSD node failure recovery I understand the concept with Ceph being able to recover from the failure of an OSD (presumably with a single OSD being on a single disk), but I?m wondering what the scenario is if an OSD server node containing multiple disks should fail. Presuming you have a server containing 8-10 disks, your duplicated placement groups could end up on the same system. From diagrams I?ve seen they show duplicates going to separate nodes, but is this in fact how it handles it? ------------------------------------------------------------------------------ CONFIDENTIALITY NOTICE: If you have received this email in error, please immediately notify the sender by e-mail at the address shown. This email transmission may contain confidential information. This information is intended only for the use of the individual(s) or entity to whom it is intended even if addressed incorrectly. Please delete it from your files if you are not the intended recipient. Thank you for your compliance. Copyright (c) 2014 Cigna ==============================================================================
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