Excerpts from Kun Feng's message of 2015-06-08 20:34:51 -0700: > Hi all, > > I'm using ceph as storage backend for Nova and Glance, and merged the > rbd-ephemeral-clone patch into Nova. As VM disks are Copy-on-write clones > of a image, I have some concerns about this: > > 1. Since hundreds of vm disks based on one base file, is there any > performance problems that IOs are loaded on this one paticular base file? >
Unless you have no ram available to VFS cache on the OSD's, this is fine. Blocks will be evenly spread to each OSD, and since these are likely to be super popular blocks, they'll likely all be served from RAM most of the time. > 2. Is it possible that the data of base file is damaged or PG/OSD > containing data of this base file out of service, resulting as all the VMs > based on that base file malfunctioned? You probably will want to read this and see if that answers your question: http://ceph.com/docs/master/architecture/#data-consistency __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: [email protected]?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
