# Re: \[Xen-devel\] blkback and bcache

- From: Joseph Glanville \<hidden\>
- Date: 2012-08-13 07:35:16 
- List: linux-bcache
- Page: https://ratatoskr.run/linux-bcache/2012/08/7635593
- Thread: https://ratatoskr.run/linux-bcache/2012/08/7635593/t.md

```text
On 13 August 2012 17:16, James Harper [ref] wrote:
> I'm having trouble using blkback under gplpv when the disk is on top of a bcache device. My devices are layered as follows:
>
> /dev/sd[ab]
> md0 (RAID1)
> bcache
> lvm
>
> It seems that bcache presents a 4K sector size to Linux, which is then reflected by lvm and in turn blkback.
>
> Obviously GPLPV isn't handling 4K sectors correctly... any suggestions as to what I might need to do to make this work properly? As a last resort I should be able to fake 512 byte sectors to Windows but would prefer that Windows knew it was dealing with a device with 4K sectors underneath.
>
> Thanks
>
> James
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel-GuqFBffKawuEi8DpZVb4nw@public.gmane.org
> http://lists.xen.org/xen-devel

This could very well be the issue I was having, I haven't been able to
pull the latest bcache code for a few days (repo down?) but if I can
help debug let me know.

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```