a1532a225a
Although this test is NOT a full test of image fleecing (as it intentionally uses just a single block device directly exported over NBD, rather than trying to set up a blockdev-backup job with multiple BDS involved), it DOES prove that qemu as a server is able to properly expose a dirty bitmap over NBD. When coupled with image fleecing, it is then possible for a third-party client to do an incremental backup by using qemu-img map with the x-dirty-bitmap option to learn which parts of the file are dirty (perhaps confusingly, they are the portions mapped as "data":false - which is part of the reason this is still in the x- experimental namespace), along with another normal client (perhaps 'qemu-nbd -c' to expose the server over /dev/nbd0 and then just use normal I/O on that block device) to read the dirty sections. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20180702191458.28741-3-eblake@redhat.com> Tested-by: John Snow <jsnow@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
50 lines
1.5 KiB
Plaintext
50 lines
1.5 KiB
Plaintext
QA output created by 223
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=== Create partially sparse image, then add dirty bitmap ===
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Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304
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wrote 2097152/2097152 bytes at offset 1048576
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2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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Testing:
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QMP_VERSION
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{"return": {}}
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{"return": {}}
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{"return": {}}
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{"return": {}}
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{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
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=== Write part of the file under active bitmap ===
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wrote 2097152/2097152 bytes at offset 2097152
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2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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=== End dirty bitmap, and start serving image over NBD ===
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{"return": {}}
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{"return": {}}
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{"return": {}}
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{"return": {}}
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{"return": {}}
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{"return": {}}
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=== Contrast normal status with dirty-bitmap status ===
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read 1048576/1048576 bytes at offset 0
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1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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read 1048576/1048576 bytes at offset 1048576
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1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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read 2097152/2097152 bytes at offset 2097152
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2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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[{ "start": 0, "length": 1048576, "depth": 0, "zero": true, "data": false},
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{ "start": 1048576, "length": 3145728, "depth": 0, "zero": false, "data": true}]
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[{ "start": 0, "length": 2097152, "depth": 0, "zero": false, "data": true},
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{ "start": 2097152, "length": 2097152, "depth": 0, "zero": false, "data": false}]
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=== End NBD server ===
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{"return": {}}
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{"return": {}}
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{"return": {}}
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*** done
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