Ilia Zykov <mail@xxxxxxxxxxx> writes: > Hello. > > Sorry, I could be wrong, but I was encountered this problem a long time ago. > You cannot transfer ext4 from a device with a phys sector 512 bite to a > device with phys 4k sector device. > As far as I remember, ext4 uses this size to perform atomic operations. > Because on the new disk it is not possible to perform an atomic > operation with data of 512 bytes, > then it is impossible to transfer such a FS. > See ENVIROMENTS for mkfs.ext4: "MKE2FS_DEVICE_SECTSIZE", > "MKE2FS_DEVICE_PHYS_SECTSIZE". Ext[234] does IO in units of blocks. In the days of 80 MB hard disks, it could use a block size of 1 or 2 KB. These days it pretty much always uses 4 KB. I'm almost certain that those environment variables are to override what the kernel detects for testing purposes, and the only thing mkfs does with this information is to force a 4K block size ( when that is the sector size ), even if the fs is small enough that it otherwise would use 1 or 2.
