I've created a downstream bug for this same issue. https://bugzilla.redhat.com/show_bug.cgi?id=1349116
On Wed, Jun 15, 2016 at 6:23 AM, <l...@jonas-server.de> wrote: > Hello guys, > > We are currently testing Ceph Jewel with object-map feature enabled: > > rbd image 'disk-22920': > size 102400 MB in 25600 objects > order 22 (4096 kB objects) > block_name_prefix: rbd_data.7cfa2238e1f29 > format: 2 > features: layering, exclusive-lock, object-map, fast-diff, > deep-flatten > flags: > > We use this RBD as disk for a kvm virtual machine with virtio-scsi and > discard=unmap. We noticed the following paremeters in /sys/block: > > # cat /sys/block/sda/queue/discard_* > 4096 > 1073741824 > 0 <- discard_zeroes_data > > While trying to do a mkfs.ext4 on the disk in VM we noticed a low > performance with using discard. > > mkfs.ext4 -E nodiscard /dev/sda1 - tooks 5 seconds to complete > mkfs.ext4 -E discard /dev/sda1 - tooks around 3 monutes > > When disabling the object-map the mkfs with discard tooks just 5 seconds. > > Do you have any idea what might cause this issue? > > Kernel: 4.2.0-35-generic #40~14.04.1-Ubuntu > Ceph: 10.2.0 > Libvirt: 1.3.1 > QEMU: 2.5.0 > > Thanks! > > Best regards, > Jonas > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Brian Andrus Red Hat, Inc. Storage Consultant, Global Storage Practice Mobile +1 (530) 903-8487
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