I have same issue, i just build new Ceph cluster for my Openstack VMs workload using rbd and i have created bunch of VM did some dd test to create big big file to test performance now i deleted all dd file but ceph still showing USED space. I tried to do from guest VM [root@c7-vm ~]# sudo fstrim / fstrim: /: the discard operation is not supported Can we run fstrim on ceph OSD node? what if i delete my VM in that case how do i run fstrim ? On Mon, Jul 23, 2018 at 6:13 PM, Ronny Aasen <ronny+ceph-users@xxxxxxxx> wrote: > On 23.07.2018 22:18, Sean Bolding wrote: > > I have XenServers that connect via iSCSI to Ceph gateway servers that use > lrbd and targetcli. On my ceph cluster the RBD images I create are used as > storage repositories in Xenserver for the virtual machine vdisks. > > > > Whenever I delete a virtual machine, XenServer shows that the repository > size has decreased. This also happens when I mount a virtual drive in > Xenserver as a virtual drive in a Windows guest. If I delete a large file, > such as an exported VM, it shows as deleted and space available. However; > when check in Ceph using ceph –s or ceph df it still shows the space being > used. > > > > I checked everywhere and it seems there was a reference to it here > https://github.com/ceph/ceph/pull/14727 but not sure if a way to trim or > discard freed blocks was ever implemented. > > > > The only way I have found is to play musical chairs and move the VMs to > different repositories and then completely remove the old RBD images in > ceph. This is not exactly easy to do. > > > > Is there a way to reclaim free space on RBD images that use Bluestore????? > What commands do I use and where do I use this from? If such command exist > do I run them on the ceph cluster or do I run them from XenServer? Please > help. > > > > > > Sean > > > > > > > > > I am not familiar with Xen, but it does sounds like you have a rbd mounted > with a filesystem on the xen server. > in that case it is the same as for other filesystems. Deleted files are just > deleted in the file allocation table, and the RBD space is "reclaimed" when > the filesystem zeroes out the now unused blocks. > > in many filesystems you would run the fstrim command to overwrite free'd > blocks with zeroes, optionally mount the fs with the the discard option. > in xenserver >6.5 this should be a button in xencenter to reclaim freed > space. > > > kind regards > Ronny Aasen > > _______________________________________________ > 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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