On Wed, 20 Sep 2017, Burkhard Linke said: > Hi, > > > On 09/20/2017 12:24 PM, Sean Purdy wrote: > >On Wed, 20 Sep 2017, Burkhard Linke said: > >>The main reason for having a journal with filestore is having a block device > >>that supports synchronous writes. Writing to a filesystem in a synchronous > >>way (e.g. including all metadata writes) results in a huge performance > >>penalty. > >> > >>With bluestore the data is also stored on a block devices, and thus also > >>allows to perform synchronous writes directly (given the backing storage is > >>handling sync writes correctly and in a consistent way, e.g. no drive > >>caches, bbu for raid controllers/hbas). And similar to the filestore journal > >Our Bluestore disks are hosted on RAID controllers. Should I set cache policy as WriteThrough for these disks then? > > It depends on the setup and availability of a BBU. If you have a BBU and > cache on the controller, using write back should be ok if you monitor the > BBU state. To be on the safe side is using write through and live with the > performance impact. We do have BBU and cache and we do monitor state. Thanks! Sean _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 |