ATVM Local Data Disk CDC Migration Report

Host: atvm-codextest-vm
Date: 03-18-2026
VM IP during run: 192.168.3.191
Project: Skidamarink
Guest OS: Oracle Linux Server 9.7

Summary
- Powered on the VM and reinstalled CMC for Linux.
- Used /dev/sdb as the source data disk and /dev/sdc as the destination data disk.
- Created an ext4 filesystem on /dev/sdb and mounted it at /mnt/disk1.
- Created a local migration session for /dev/sdb -> /dev/sdc.
- Wrote about 1 GiB of data to /mnt/disk1/aw.dat with fio while the session was active.
- Waited for the session to resynchronize and return to TRACKING with remaining data at 0.
- Performed cutover, then final cutover.
- Unmounted the source mount after final cutover, deleted the session, mounted the destination disk at /mnt/destination, and verified the migrated file.

Disk Layout
- Source disk: /dev/sdb
- Source filesystem: ext4
- Source mountpoint: /mnt/disk1
- Destination disk: /dev/sdc
- Destination mountpoint after completion: /mnt/destination

CMC Reinstall
- Registration code: CMC_GCSTAGE_REGISTRATION_CODE from /home/aw/code/cds/.env.credentials.local
- Endpoint: portal.gcstage.cloud.nonprod.cirrusdata.com:443
- Result: successful

Migration Session
- Local session ID: 1
- Session UUID: 6d086de2-de8f-40c9-8a1c-c22712abce28
- Description: aw local ext4 validation
- Auto resync interval after explicit update: 5s

fio Write
- Command intent: write about 1 GiB to /mnt/disk1/aw.dat
- File created: /mnt/disk1/aw.dat
- File size: 1.0G
- fio runtime: 1924 ms
- fio bandwidth: 532 MiB/s
- fio write IOPS: 532

Source File Verification
- Source path: /mnt/disk1/aw.dat
- SHA-256: b695f7743705a16ef6c346d7d3a962d3608d10af4eae12e7474e2224efc0fe47

Key Session State
- Session created successfully.
- Initial file write produced changed data on the session.
- Explicit sync completed and the session returned to TRACKING with remaining = 0.
- Session then entered cutover/cmotion successfully.

Important Session Events
- SESSION_SYNCHRONIZED at 2026-03-19T01:45:52.643383535Z
- SESSION_ENTERED_CMOTION at 2026-03-19T01:45:53.440862866Z
- SESSION_FINAL_CUTOVER_EXECUTED at 2026-03-19T01:46:08.831400665Z
- SESSION_DELETED at 2026-03-19T01:46:12.798177270Z

Post-Cutover Handling
- /mnt/disk1 unmounted before session deletion.
- Migration session deleted successfully.
- No migration sessions remained after deletion.

Destination Verification
- Destination disk mounted at /mnt/destination from /dev/sdc
- Destination file: /mnt/destination/aw.dat
- Destination SHA-256: b695f7743705a16ef6c346d7d3a962d3608d10af4eae12e7474e2224efc0fe47

Verification Result
- Source and destination SHA-256 values match exactly.
- Data verification passed.

Final Guest Disk State
- /dev/sdb present and not mounted
- /dev/sdc mounted at /mnt/destination as ext4

Notes
- The session remained in TRACKING with changed data after the fio write until an explicit auto-resync interval and sync were applied.
- Cutover succeeded first; final cutover had to wait until the session transitioned from TRACKING to STANDING_IN.