Linux Device Mapper Adding An "Emulated Block Size" Target
Written by Michael Larabel in Linux Storage on 3 May 2020 at 06:56 AM EDT. 14 Comments
A new target for Linux's Device Mapper is EBS, the Emulated Block Size.

Device Mapper, a key piece to Linux Soft RAID, dm-crypt, and other storage capabilities, is with Linux 5.8 seeing the new EBS target. EBS allows for emulating a smaller block size than the native capabilities of the underlying storage device. The original use-case for DM EBS is for emulating 512 byte sectors on 4K native disks.

The Device Mapper Emulated Block Size target supports logical block sizes from 512 to 4096 bytes. This new target was contributed by Red Hat. Basically it's similar to the 512e local block size emulation offered by some disk drives currently while this emulation is implemented within the Linux block layer for dealing with software that isn't optimized for 4K sectors.

This simple DM target is currently queued as part of the Device Mapper changes expected for the Linux 5.8 cycle kicking off next month.
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