Re: [PATCH 2/6] chunkd: change the prefix length of object pathname from 4 to 3

[Jeff Garzik <jeff@garzik.org>]

On 01/11/2010 07:25 AM, Akinobu Mita wrote:
> The volume directory may have 2^16 (=65536) directories because
> prefix length of object pathname is 4 bytes. But ext3 filesystem can
> only have EXT_LINK_MAX (32000) directories.
>
> This changes the prefix length from 4 bytes to 3 bytes and breaks
> the volume data format compatibility with older version.
>
> Now the maximum count of links in volume directory is 2^12 (=4096)
> and it doesn't exceed ext3's upper limit of max links.
>
> Signed-off-by: Akinobu Mita<akinobu.mita@gmail.com>
> ---
>   server/be-fs.c |    2 +-
>   1 files changed, 1 insertions(+), 1 deletions(-)

hey, welcome, new contributor!

This patch makes sense, but it also raises the question of whether or 
not we should move to a two-level directory scheme, eg.

	123/456/7890ABCDEF
     rather than
	123/4567890ABCDEF

to limit the size of the top-level directories.  It really depends on 
the object counts a typical chunkd node will be seeing.  As with the 
other patch, I will give this some thought after sleep.

Comments welcome!

	Jeff