On 01/12/2010 03:28 AM, Akinobu Mita wrote:
2010/1/12 Jeff Garzik<jeff@xxxxxxxxxx>:
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@xxxxxxxxx>
---
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.
Two-level directory scheme looks good.
I will do it unless someone thinks 536,870,912,000(=4096*4096*32000)
objects in one table is not enough :)
FWIW, 32000 is only the limit on directories-with-a-directory. You can
easily have millions of regular files in a single ext3 directory. So it
is really 4096*4096*millions.
Jeff
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