> Your use case sounds it might profit from the rados cache tier > feature. It's a rarely used feature because it only works in very > specific circumstances. But your scenario sounds like it might work. > Definitely worth giving it a try. Also, dm-cache with LVM *might* > help. > But if your active working set is really just 400GB: Bluestore cache > should handle this just fine. Don't worry about "unequal" > distribution, every 4mb chunk of every file will go to a random OSD.
I tried it out - and will do it more but Initial tests didnt really convince me - but I'll try more. > One very powerful and simple optimization is moving the metadata pool > to SSD only. Even if it's just 3 small but fast SSDs; that can make a > huge difference to how fast your filesystem "feels". They are ordered and will hopefully arrive very soon. Can I: 1) Add disks 2) Create pool 3) stop all MDS's 4) rados cppool 5) Start MDS .. Yes, thats a cluster-down on CephFS but shouldn't take long. Or is there a better guide? -- Jesper _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
