Hi, rbd_id.vm-100-disk-1 is only a "meta object", IIRC, it's contents will get you a "prefix", which then gets you on to rbd_header.<prefix>, rbd_header.prefix contains block size, striping, etc. The actual data bearing objects will be named something like rbd_data.prefix.%-016x.
Example - vm-100-disk-1 has the prefix 86ce2ae8944a, the first <block size> of that image will be named rbd_data. 86ce2ae8944a.000000000000, the second <block size> will be 86ce2ae8944a.000000000001, and so on, chances are that one of these objects are mapped to a pg which has both host3 and host4 among it's replicas. An rbd image will end up scattered across most/all osds of the pool it's in. Cheers, -KJ On Fri, Mar 17, 2017 at 12:30 PM, Adam Carheden <carhe...@ucar.edu> wrote: > I have a 4 node cluster shown by `ceph osd tree` below. Monitors are > running on hosts 1, 2 and 3. It has a single replicated pool of size > 3. I have a VM with its hard drive replicated to OSDs 11(host3), > 5(host1) and 3(host2). > > I can 'fail' any one host by disabling the SAN network interface and > the VM keeps running with a simple slowdown in I/O performance just as > expected. However, if 'fail' both nodes 3 and 4, I/O hangs on the VM. > (i.e. `df` never completes, etc.) The monitors on hosts 1 and 2 still > have quorum, so that shouldn't be an issue. The placement group still > has 2 of its 3 replicas online. > > Why does I/O hang even though host4 isn't running a monitor and > doesn't have anything to do with my VM's hard drive. > > > Size? > # ceph osd pool get rbd size > size: 3 > > Where's rbd_id.vm-100-disk-1? > # ceph osd getmap -o /tmp/map && osdmaptool --pool 0 --test-map-object > rbd_id.vm-100-disk-1 /tmp/map > got osdmap epoch 1043 > osdmaptool: osdmap file '/tmp/map' > object 'rbd_id.vm-100-disk-1' -> 0.1ea -> [11,5,3] > > # ceph osd tree > ID WEIGHT TYPE NAME UP/DOWN REWEIGHT PRIMARY-AFFINITY > -1 8.06160 root default > -7 5.50308 room A > -3 1.88754 host host1 > 4 0.40369 osd.4 up 1.00000 1.00000 > 5 0.40369 osd.5 up 1.00000 1.00000 > 6 0.54008 osd.6 up 1.00000 1.00000 > 7 0.54008 osd.7 up 1.00000 1.00000 > -2 3.61554 host host2 > 0 0.90388 osd.0 up 1.00000 1.00000 > 1 0.90388 osd.1 up 1.00000 1.00000 > 2 0.90388 osd.2 up 1.00000 1.00000 > 3 0.90388 osd.3 up 1.00000 1.00000 > -6 2.55852 room B > -4 1.75114 host host3 > 8 0.40369 osd.8 up 1.00000 1.00000 > 9 0.40369 osd.9 up 1.00000 1.00000 > 10 0.40369 osd.10 up 1.00000 1.00000 > 11 0.54008 osd.11 up 1.00000 1.00000 > -5 0.80737 host host4 > 12 0.40369 osd.12 up 1.00000 1.00000 > 13 0.40369 osd.13 up 1.00000 1.00000 > > > -- > Adam Carheden > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Kjetil Joergensen <kje...@medallia.com> SRE, Medallia Inc Phone: +1 (650) 739-6580
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