Stephen, >> > Sector size (logical/physical): 512 bytes / 512 bytes >> > I/O size (minimum/optimal): 4096 bytes / *33553920* bytes > [ 0.000000] Linux version 5.4.0-144-generic (buildd@lcy02-amd64-089) (gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04.1)) #161-Ubuntu SMP Fri Feb 3 14:49:04 UTC 2023 (Ubuntu 5.4.0-144.161-generic 5.4.229) This issue was (hopefully) addressed by 631669a256f9 ("scsi: sd: Optimal I/O size should be a multiple of reported granularity") which was merged in 5.19. -- Martin K. Petersen Oracle Linux Engineering