Hi Stefan, If the majority of your hot data fits on the cache tier you will see quite a marked improvement in read performance and similar write performance (assuming you would have had your hdds backed by SSD journals). However for data that is not in the cache tier you will get 10-20% less read performance and anything up to 10x less write performance. This is because a cache write miss has to read the entire object from the backing store into the cache and then modify it. The read performance degradation will probably be fixed in Hammer with proxy reads, but writes will most likely still be an issue. Nick > -----Original Message----- > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of > Stefan Priebe - Profihost AG > Sent: 11 March 2015 07:27 > To: ceph-users@xxxxxxxxxxxxxx > Subject: Firefly Tiering > > Hi, > > has anybody successfully tested tiering while using firefly? How much does it > impact performance vs. a normal pool? I mean is there any difference > between a full SSD pool und a tiering SSD pool with SATA Backend? > > Greets, > Stefan > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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