On Sun, 2002-09-29 at 16:28, L A Walsh wrote:
> I wanted to use an alternate block size on my SCSI hard disk.
>
> I did a low-level reformat to use 4096 and got an additional 10.3% in hard
> disk space. (17783MB -> 19627).
>
> I can't think of a reason why I'd want to have a 512 byte block when the
> smallest allocation unit on a disk is 4K.
>
> However -- I ran into a hard coded reason with XFS -- it's hard coded to use
> 512 byte blocks.
>
> Is there a reason for this? Am I missing something? Is it a bug, or is there
> some reason why xfs can't handle different sized blocks?
>
> -l
>
Its pretty hard coded in the code that the disk is addressed in 512 byte
sectors. Changing this has been discussed, but it is more complex than
just changing a constant in the code. The original design while very
scalable, did not consider sector sizes over than 512 as being a
possibility. Note that this is not the filesystem block size, most
metadata is 4K in size by default.
Steve
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