Add CBT (Changed Block Tracking) test suite by Lankou66 · Pull Request #541 · xcp-ng/xcp-ng-tests

Lankou66 · 2026-05-20T09:45:22Z

Add CBT (Changed Block Tracking) test suite

This PR implements a test suite for the CBT feature across following SR types:

EXT
LVM
LVMoISCSI
LVMoHBA
NFS
XFS
ZFS

glehmann · 2026-06-18T09:00:59Z

@Lankou66 could you rebase on master before we review? There are a lot of conflicts

stormi · 2026-06-18T10:10:01Z


 ImageFormat = Literal['qcow2', 'raw', 'vhd']

+


Not a necessary change?

stormi

I had a quick look but stopped due to:

whitespace changes that are not relevant to this PR
missing commit messages and commit titles that don't fully follow the conventions: https://docs.xcp-ng.org/project/development-process/commit-message-conventions/

As time is precious, I'll consider reviewing once this is fixed.

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

glehmann

On the commit organization, I would have preferred, to ease the review, that each commit introduce a test or a set of related tests, with the generic method in storage.py, the implementation for all the SR types, and an explanation of what it does in the commit description.

glehmann · 2026-06-18T20:41:22Z

+    result = host.ssh(f'test -f {log_path}', check=False, simple_output=False)
+    assert result.returncode == 0, f"CBT log not found at {log_path}"


Suggested change

result = host.ssh(f'test -f {log_path}', check=False, simple_output=False)

assert result.returncode == 0, f"CBT log not found at {log_path}"

assert host.file_exists(log_path), f"CBT log not found at {log_path}"

glehmann · 2026-06-18T20:41:22Z

+    result = host.ssh(f'stat -c %s {log_path}', simple_output=False)
+    log_size = int(result.stdout.strip())


Suggested change

result = host.ssh(f'stat -c %s {log_path}', simple_output=False)

log_size = int(result.stdout.strip())

log_size = int(host.ssh(f'stat -c %s {log_path}').strip())

glehmann · 2026-06-18T20:41:23Z

+    result = host.ssh(f'lvs --noheadings -o lv_name {vg_name}', simple_output=False)
+    assert cbt_log_name in result.stdout, \
+        f"CBT log LV {cbt_log_name} not found in VG {vg_name}"


Suggested change

result = host.ssh(f'lvs --noheadings -o lv_name {vg_name}', simple_output=False)

assert cbt_log_name in result.stdout, \

f"CBT log LV {cbt_log_name} not found in VG {vg_name}"

result = host.ssh(f'lvs --noheadings -o lv_name {vg_name}')

assert cbt_log_name in result, f"CBT log LV {cbt_log_name} not found in VG {vg_name}"

glehmann · 2026-06-18T20:41:23Z

+    result = host.ssh(f'test -f {log_path}', check=False, simple_output=False)
+    assert result.returncode != 0, f"CBT log should not exist at {log_path}"


Suggested change

result = host.ssh(f'test -f {log_path}', check=False, simple_output=False)

assert result.returncode != 0, f"CBT log should not exist at {log_path}"

assert host.file_exists(log_path), f"CBT log should not exist at {log_path}"

glehmann · 2026-06-18T20:41:23Z

+    result = host.ssh(f'lvs --noheadings -o lv_name {vg_name}', simple_output=False)
+    assert cbt_log_name not in result.stdout, \
+        f"CBT log LV {cbt_log_name} should not exist in VG {vg_name}"


Suggested change

result = host.ssh(f'lvs --noheadings -o lv_name {vg_name}', simple_output=False)

assert cbt_log_name not in result.stdout, \

f"CBT log LV {cbt_log_name} should not exist in VG {vg_name}"

result = host.ssh(f'lvs --noheadings -o lv_name {vg_name}')

assert cbt_log_name not in result, f"CBT log LV {cbt_log_name} should not exist in VG {vg_name}"

glehmann · 2026-06-18T20:41:23Z

+
+
+@contextmanager
+def cbt_enabled(vdi: VDI) -> Generator[VDI, None, None]:


Shouldn't this rather be a fixture?

Fixtures has a great advantage over context manager to deal with resources: when a test fails, the debugger is started before the resources are destroyed. The teardown is executed once you exit the debugger. It helps a lot to investigate in case of failure.

This is probably also true—at least I would ask the same question—for the other context managers.

glehmann · 2026-06-18T20:41:23Z

+            vm.disconnect_vdi(vdi)
+            vm.shutdown(verify=True)
+            second = vdi.snapshot()
+            stack.callback(second.destroy)


The same idea as for the context manager applies here.

We have a defer fixture which does the same thing, but ensures that the resources are preserved when entering the debugger.

glehmann · 2026-06-18T20:41:23Z

+            for i in range(len(snapshots) - 1):
+                assert verify_changed_blocks_detected(snapshots[i], snapshots[i + 1])
+                logging.info(f"Changes detected: snap{i} -> snap{i + 1}")
+        finally:


Same for the try/finally blocks, defer helps a lot.

Lankou66 force-pushed the gru_cbt_test branch 7 times, most recently from ee415bc to 71b7668 Compare June 16, 2026 17:49

Lankou66 changed the title ~~Implement CBT Test~~ Add CBT (Changed Block Tracking) test suite Jun 18, 2026

Lankou66 marked this pull request as ready for review June 18, 2026 08:47

Lankou66 requested review from a team as code owners June 18, 2026 08:47

stormi reviewed Jun 18, 2026

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stormi requested changes Jun 18, 2026

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Lankou66 added 8 commits June 18, 2026 12:21

implement CBT helpers in lib/vdi.py and tests/storage/storage.py

80af360

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

implement cbt_tests on extSR

715d4a7

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

implement cbt_tests on LVMoISCSI sr

8a1bf02

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

implement cbt_tests on lvmSR

28b673a

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

implement cbt_tests on lvmohba sr

2eb3d4e

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

implement cbt tests on XFSSR

51abf89

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

implement cbt_tests on nfs_sr

afb58db

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

implement cbt_tests on ZFSsr

9bc337b

Signed-off-by: Goulven Riou <goulven.riou@vates.tech>

Lankou66 force-pushed the gru_cbt_test branch from 71b7668 to 9bc337b Compare June 18, 2026 10:34

glehmann reviewed Jun 18, 2026

View reviewed changes

Lankou66 marked this pull request as draft July 28, 2026 08:37

This was referenced Aug 24, 2026

blktap-3.55.5-9.4 xcp-ng-rpms/blktap#27

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Release 3.55.5-9.4 xcp-ng-rpms/blktap#28

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Add CBT (Changed Block Tracking) test suite - #541

Add CBT (Changed Block Tracking) test suite#541
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		result = host.ssh(f'test -f {log_path}', check=False, simple_output=False)
		assert result.returncode == 0, f"CBT log not found at {log_path}"

	result = host.ssh(f'test -f {log_path}', check=False, simple_output=False)
	assert result.returncode == 0, f"CBT log not found at {log_path}"
	assert host.file_exists(log_path), f"CBT log not found at {log_path}"

		result = host.ssh(f'stat -c %s {log_path}', simple_output=False)
		log_size = int(result.stdout.strip())

	result = host.ssh(f'stat -c %s {log_path}', simple_output=False)
	log_size = int(result.stdout.strip())
	log_size = int(host.ssh(f'stat -c %s {log_path}').strip())

		result = host.ssh(f'test -f {log_path}', check=False, simple_output=False)
		assert result.returncode != 0, f"CBT log should not exist at {log_path}"



		@contextmanager
		def cbt_enabled(vdi: VDI) -> Generator[VDI, None, None]:

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Lankou66 commented May 20, 2026 •

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