Since this is a continuation of some related testing just thought I'd note here for anyone interested some unexpected behavior from check's reporting when used without --repair following previously zeroed out chunks.
I found that after --repair had zeroed an intentionally corrupted chunk, then I ran a create backup successfully, that if I next ran check but without --repair it would report as having healed the missing chunks, when it actually hadn't.
Steps:
Removed the repo hints, index and integrity files as part of this test (was checking how Borg would respond to both missing repo metadata and a corrupted chunk file simultaneously).
Intentionally corrupted the largest data file in the repo. Since I have a PNG image in the source data larger than other files in the source data these larger data files have always contained the image data for these tests.
Ran check with --verify-data and --repair. This zeroed out the corrupted chunks.
Ran a successful backup with create.
Ran check with --verify-data but without--repair. And this is where it reported the PNG image as being healed in all backups (removed time values from the log):
However after using mount to check if it had actually healed I found only the latest backup contained the openable PNG image. While the prior backups all errored when opening it.
So I ran check with --repair and it reported the heals like the prior output but this time it actually worked for all the backups it reported (confirmed by re-mounting the backups).
borg 1.4.0
Since this is a continuation of some related testing just thought I'd note here for anyone interested some unexpected behavior from
check's reporting when used without--repairfollowing previously zeroed out chunks.I found that after
--repairhad zeroed an intentionally corrupted chunk, then I ran acreatebackup successfully, that if I next rancheckbut without--repairit would report as having healed the missing chunks, when it actually hadn't.Steps:
hints,indexandintegrityfiles as part of this test (was checking how Borg would respond to both missing repo metadata and a corrupted chunk file simultaneously).datafile in the repo. Since I have a PNG image in the source data larger than other files in the source data these largerdatafiles have always contained the image data for these tests.checkwith--verify-dataand--repair. This zeroed out the corrupted chunks.create.checkwith--verify-databut without--repair. And this is where it reported the PNG image as being healed in all backups (removedtimevalues from the log):... {"type": "log_message", "message": "borg-backup-test-1: home/user/Documents/test-data/test.png: Healed previously missing file chunk! (Byte 0-475076, Chunk acd0521e02a47fde43e172300e6728268517a5676ebe7079007644aff35f1dac).", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "borg-backup-test-1: home/user/Documents/test-data/test.png: Completely healed previously damaged file!", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "Analyzing archive borg-backup-test-2 (5/8)", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "borg-backup-test-2: home/user/Documents/test-data/test.png: Healed previously missing file chunk! (Byte 0-475076, Chunk acd0521e02a47fde43e172300e6728268517a5676ebe7079007644aff35f1dac).", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "borg-backup-test-2: home/user/Documents/test-data/test.png: Completely healed previously damaged file!", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "Analyzing archive borg-backup-test-3 (6/8)", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "borg-backup-test-3: home/user/Documents/test-data/test.png: Healed previously missing file chunk! (Byte 0-475076, Chunk acd0521e02a47fde43e172300e6728268517a5676ebe7079007644aff35f1dac).", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "borg-backup-test-3: home/user/Documents/test-data/test.png: Completely healed previously damaged file!", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "Analyzing archive borg-backup-test-4 (7/8)", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "borg-backup-test-4: home/user/Documents/test-data/test.png: Healed previously missing file chunk! (Byte 0-475076, Chunk acd0521e02a47fde43e172300e6728268517a5676ebe7079007644aff35f1dac).", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "borg-backup-test-4: home/user/Documents/test-data/test.png: Completely healed previously damaged file!", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "Analyzing archive borg-backup-test-5 (8/8)", "levelname": "INFO", "name": "borg.archive"} {"type": "log_message", "message": "Archive consistency check complete, no problems found.", "levelname": "INFO", "name": "borg.archive"}mountto check if it had actually healed I found only the latest backup contained the openable PNG image. While the prior backups all errored when opening it.checkwith--repairand it reported the heals like the prior output but this time it actually worked for all the backups it reported (confirmed by re-mounting the backups).Originally posted by @chocmake in https://github.com/borgbackup/borg/discussions/8527#discussioncomment-11195598