So far the "disk" resource reported by Mesos refers to the disk where sandboxes will be created. By default, persistent volumes will be created under the same slave work_dir. We could pretty easily provide a separate flag so that all persistent volumes can go on a different disk than all sandboxes, but the real answer would be proper multi-disk support in the resource offers, and then each framework can choose which disk to use for its sandbox and/or volumes. Multi-disk support is on the roadmap, but I don't know if there's any design/doc for it yet besides MESOS-191 <https://issues.apache.org/jira/browse/MESOS-191>.
You might also be interested in MESOS-2406 <https://issues.apache.org/jira/browse/MESOS-2406> for migrating pre-existing data in Mesos persistent volumes. On Tue, Mar 31, 2015 at 11:35 PM, Maxime Brugidou <maxime.brugi...@gmail.com > wrote: > Hi, > > We have been talking more and more about the long-awaited feature at > https://issues.apache.org/jira/browse/MESOS-1554 > > I started looking at what have been done in the APIs and as far as I > understand framework will be able to reserved and unreserve resources with > DiskInfo. Each DiskInfo has a persistent id and a volume. The host_path in > DiskInfo is ignored (only used for containerInfo). > > Question: how could can we tell the mesos slave which disks to allocate > and how do we identify disks? My slaves have multiple disks mounted, with > different characteristics and sizes. Some are more appropriate for HDFS use > and some for Cassandra. Right now everything is done out of band but I > wonder how this could be done with persistent resources. > > Same question with dynamic reservations: how can I reserve a disk and not > just some disk space quota? I clearly don't want my applications to all > work on the sane disk (really bad for IO). > > Maybe I missed the design doc or there is a more detailed description of > the future feature somewhere? > > Thanks for your help, > Maxime >
