On Thu, Mar 2, 2017 at 8:09 AM, Massimiliano Cuttini <max@xxxxxxxxxxxxx> wrote: > Ok, > > then, if the command comes from the hypervisor that hold the image is it > safe? No, it needs to be issued from the guest VM -- not the hypervisor that is running the guest VM. The reason is that it's a black box to the hypervisor and it won't know what sectors can be safely discarded. > But if the guest VM on the same Hypervisor try to using the image, what > happen? If you trim from outside the guest, I would expect you to potentially corrupt the image (if the fstrim tool doesn't stop you first since the filesystem isn't mounted). > Are these safe tools? (aka: safely exit with error instead of try the > command and ruin the image?). > Should I consider a snapshot before go? > As I mentioned, the only safe way to proceed would be to run the trim from within the guest VM or wait until Ceph adds the rbd CLI tooling to safely sparsify an image. > > > > Il 02/03/2017 13:53, Jason Dillaman ha scritto: >> >> In that case, the trim/discard requests would need to come directly >> from the guest virtual machines to avoid damaging the filesystems. We >> do have a backlog feature ticket [1] to allow an administrator to >> transparently sparsify a in-use image via the rbd CLI, but no work has >> been started on it yet. >> >> [1] http://tracker.ceph.com/issues/13706 >> >> On Thu, Mar 2, 2017 at 5:16 AM, Massimiliano Cuttini <max@xxxxxxxxxxxxx> >> wrote: >>> >>> Thanks Jason, >>> >>> I need some further info, because I'm really worried about ruin my data. >>> On this pool I have only XEN virtual disks. >>> Did I have to run the command directly on the "pool" or on the "virtual >>> disks" ? >>> >>> I guess that I have to run it on the pool. >>> As Admin I don't have access to local filesystem of the customer's >>> virtual >>> disk and neither I can temporarly mount it to trim them. >>> Are my assumptions right? >>> >>> Another info: did I need to umount the image from every device that is >>> actually using the image while I'm trimming it? >>> >>> Thanks, >>> Max >>> >>> >>> >>> Il 01/03/2017 20:11, Jason Dillaman ha scritto: >>>> >>>> You should be able to issue an fstrim against the filesystem on top of >>>> the nbd device or run blkdiscard against the raw device if you don't >>>> have a filesystem. >>>> >>>> On Wed, Mar 1, 2017 at 1:26 PM, Massimiliano Cuttini <max@xxxxxxxxxxxxx> >>>> wrote: >>>>> >>>>> Dear all, >>>>> >>>>> i use the rbd-nbd connector. >>>>> Is there a way to reclaim free space from rbd image using this >>>>> component >>>>> or >>>>> not? >>>>> >>>>> >>>>> Thanks, >>>>> Max >>>>> >>>>> _______________________________________________ >>>>> ceph-users mailing list >>>>> ceph-users@xxxxxxxxxxxxxx >>>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >>>> >>>> >>>> >> >> > -- Jason _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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