On Thu, Sep 10, 2015 at 1:07 PM, Kyle Hutson <kylehutson@xxxxxxx> wrote: > A 'rados -p cachepool ls' takes about 3 hours - not exactly useful. > > I'm intrigued that you say a single read may not promote it into the cache. > My understanding is that if you have an EC-backed pool the clients can't > talk to them directly, which means they would necessarily be promoted to the > cache pool so the client could read it. Is my understanding wrong? You're not wrong (although you may be in the future!), but for instance there is code somewhere (in Infernalis-to-be, I think?) that will simply proxy the read through the cache OSD, without actually reading up the data. > > I'm also wondering if it's possible to use RAM as a read-cache layer. > Obviously, we don't want this for write-cache because of power outages, > motherboard failures, etc., but it seems to make sense for a read-cache. Is > that something that's being done, can be done, is going to be done, or has > even been considered? We don't do anything special to make use of RAM because the linux page cache is generally more intelligent about it than we could be. Sufficiently hot objects will be in RAM without us needing to do anything special. ;) -Greg _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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