I'm not sure why I never received the original list email, so I apologize for the delay. Is /dev/sda1, from your example, fresh with no data to actually discard or does it actually have lots of data to discard? Thanks, On Wed, Jun 22, 2016 at 1:56 PM, Brian Andrus <bandrus@xxxxxxxxxx> wrote: > 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, <list@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx >> 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 > > > _______________________________________________ > 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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