> On 17 Mar 2016, at 17:28, Erik Schwalbe <erik.schwa...@canoo.com> wrote: > > Hi, > > at the moment I do some tests with SSD's and ceph. > My Question is, how to mount an SSD OSD? With or without discard option? I recommend running without discard but running "fstrim" command every now and then (depends on how fast your SSD is - some SSDs hang for quite a while when fstrim is run on them, test it) > Where should I do the fstrim, when I mount the OSD without discard? On the > ceph storage node? Inside the vm, running on rbd? > discard on the SSD itself makes garbage collection easier - that might make the SSD faster and it can last longer (how faster and how longer depends on the SSD, generally if you use DC-class SSDs you won't notice anything) discard in the VM (assuming everything supports it) makes thin-provisioning more effective, but you (IMO) need virtio-scsi for that. I have no real-life experience whether Ceph actually frees the unneeded space even if you make it work... > What is the best practice there. > > Thanks for your answers. > > Regards, > Erik > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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