On Tue, Jun 24, 2014 at 8:29 AM, Shayan Saeed <shayansaeed93@xxxxxxxxx> wrote: > Hi, > > CRUSH placement algorithm works really nice with replication. However, > with erasure code, my cluster has some issues which require making > changes that I cannot specify with CRUSH maps. > Sometimes, depending on the type of data, I would like to place them > on different OSDs but in the same pool. Why do you want to keep the data in the same pool? > > I realize that to disable the CRUSH placement algorithm and replacing > it with my own custom algorithm, such as random placement algo or any > other, I have to make changes in the source code. I want to ask if > there is an easy way to do this without going into every code file and > looking where the mapping from objects to PG is done and changing > that. Is there some configuration option which disables crush and > points to my own placement algo file for doing custom placement. What you're asking for really doesn't sound feasible, but the thing that comes closest would probably be resurrecting the "pg preferred" mechanisms in CRUSH and the Ceph codebase. You'll have to go back through the git history to find it, but once upon a time we supported a mechanism that let you specify a specific OSD you wanted a particular object to live on, and then it would place the remaining replicas using CRUSH. -Greg Software Engineer #42 @ http://inktank.com | http://ceph.com > > Let me know about the most neat way to go about it. Appreciate any > help I can get. > > Regards, > Shayan Saeed > Research Assistant, Systems Research Lab > University of Illinois Urbana-Champaign > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
