[chassis] Clearwater2 cards are going to read-only

[arlakshm]

The clearwater 2 linecards are going to read-only mode during sonic-mgmt. nightly test.

Message from dmsg

[  650.871471] EXT4-fs (loop1): I/O error while writing superblock
[  650.871473] EXT4-fs (loop1): previous I/O error to superblock detected
[  650.871474] EXT4-fs error (device loop1): ext4_journal_check_start:83: Detected aborted journal
[  650.871475] EXT4-fs (loop1): Remounting filesystem read-only
[  650.871504] Buffer I/O error on dev loop1, logical block 0, lost sync page write
[  650.871510] EXT4-fs (loop1): I/O error while writing superblock
[  650.871511] EXT4-fs error (device loop1): ext4_journal_check_start:83: Detected aborted journal
[  650.871514] EXT4-fs (loop1): failed to convert unwritten extents to written extents -- potential data loss!  (inode 12, error -30)
[  650.871516] Buffer I/O error on device loop1, logical block 429626
[  650.871519] Buffer I/O error on device loop1, logical block 429627
[  650.871520] Buffer I/O error on device loop1, logical block 429628
[  650.871521] Buffer I/O error on device loop1, logical block 429629
[  650.871575] EXT4-fs (loop1): failed to convert unwritten extents to written extents -- potential data loss!  (inode 13, error -30)
[  650.963391] EXT4-fs (loop1): This should not happen!! Data will be lost

[kenneth-arista]

@arlakshm as discussed offline, mounting /tmp and /var as tmpfs will help minimize potential flash corruption due to power loss, etc.

[kenneth-arista]

In terms of logs/info to collect,

• dmesg: logs are stored in a ring buffer and thus should be queried ASAP after a failure is seen
• smartctl -a /dev/sda1
• /var/log/syslog
• journalctl

[rlhui]

@kenneth-arista is root cause confirmed/known?

[kenneth-arista]

The trigger is not specific to CL2. But instead it is a known behavior of EXT4 when there is some file system corruption due to unclean unmounts (e.g. sudden power loss, etc.).

[kenneth-arista]

Looks like other platforms are moving /var/log to tmpfs to minimize writes to flash. See sonic-net/sonic-buildimage#15077

[kenneth-arista]

The problem is understood and thus closing this issue. We'll be pushing some changes in the platform code that should help mitigate occurrences in sonic-mgmt testing.