I have an XFS partition with a 64k blocksize. But I can only mount it in Ubuntu 10.10 when the blocksize is the default of 4k. How can I mount a partition with the larger blocksize?

This works:

sudo mkfs.xfs /dev/sdb1 -b size=4k -d agcount=32 -l size=128m -f
sudo mount /dev/sdb1 /mnt/media

This doesn't work:

sudo mkfs.xfs /dev/sdb1 -b size=64k -d agcount=32 -l size=128m -f
sudo mount /dev/sdb1 /mnt/media
mount: Function not implemented

1 Answer 1


That's because Linux will allow you to create an XFS partition with large block-sizes, but can only mount an XFS partition that has a block size at or smaller than the memory page size. The memory block size set in all pre-compiled kernels of common distros is 4KB. Check it with getconf PAGE_SIZE. You can set it higher, but it requires compiling your own kernel.

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