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quyk

Member

Registered: 2020-04-22

Posts: 11

Why would physical sector size change when accessing device?

I have an SSD (Samsung SSD 980) connected to my computer via a USB-C enclosure. I've noticed that while I am using the device, the physical sector size is sometimes reported as 2048B and sometimes as 8388608B (8MiB). This caused a lot of trouble when partitioning it because I couldn't align the partition. While I've heard that this number doesn't represent actual physical sector size for solid state disks, I can't find any information about why it would change. Is there some reason this might happen?

Here's the information printed from parted:

Model: Samsung SSD 980 1TB (scsi)
Disk /dev/sdb: 953870MiB
Sector size (logical/physical): 512B/2048B
Partition Table: gpt
Disk Flags: 

Number  Start    End        Size       File system  Name         Flags
 1      8.00MiB  476936MiB  476928MiB               crypt

After mounting and unmounting the encrypted partition, here's the same output:

Model: Samsung SSD 980 1TB (scsi)
Disk /dev/sdb: 953870MiB
Sector size (logical/physical): 512B/8388608B
Partition Table: gpt
Disk Flags: 

Number  Start    End        Size       File system  Name         Flags
 1      8.00MiB  476936MiB  476928MiB               crypt