Hello, my crappy test cluster was rendered inoperational by an IP renumbering that wasn't planned and forced on me during a DC move, so I decided to start from scratch and explore the fascinating world of Luminous/bluestore and all the assorted bugs. ^_- (yes I could have recovered the cluster by setting up a local VLAN with the old IPs, extract the monmap, etc, but I consider the need for a running monitor a flaw, since all the relevant data was present in the leveldb). Anyways, while I've read about bluestore OSD cache in passing here, the back of my brain was clearly still hoping that it would use pagecache/SLAB like other filesystems. Which after my first round of playing with things clearly isn't the case. This strikes me as a design flaw and regression because: 1. Completely new users may think that bluestore defaults are fine and waste all that RAM in their machines. 2. Having a per OSD cache is inefficient compared to a common cache like pagecache, since an OSD that is busier than others would benefit from a shared cache more. 3. A uniform OSD cache size of course will be a nightmare when having non-uniform HW, either with RAM or number of OSDs. Christian -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Rakuten Communications _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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