2011-04-01 14:16:53

by Mason

[permalink] [raw]
Subject: Re: ext2 large block size > page size

Hello again,

Mason wrote:

> As far as I can tell from a quick Google search,
> there was a push in 2007 to add support for large
> blocks in some file-systems, in particular ext2.
>
> e.g. cf. http://lwn.net/Articles/239090/

The page above describes one of the proposed patch, and
the following article by Jonathan Corbet gives an overview
of the issues.

http://lwn.net/Articles/232757/

> Was this ever accepted into the main line?
> (It seems to have lived within -mm for a while)
>
> A few years later, I'm trying to mount a HDD
> which was ext2-formatted with 32k blocks.
>
> And mount is failing (with a strange "block size
> too small" error message).
>
> I'm trying this in Fedora 14
> 2.6.35.6 kernel
> 1.41.12 e2fsprogs

To add insult to injury, Ext2Fsd(*) an ext2 IFS (Installable
File System) for Windows, accepts large-block ext2 partitions.

(*) http://www.ext2fsd.com/

> Is the support for large blocks in ext2 not compiled in
> this generic kernel ? Or was the patch never accepted ?
>
> I'm working with a ST Microelectronics set-top box.
> Here are a few performance results for a 2TB USB HDD:
> block size 4k : format = 151 s / mount = 242 s
> block size 8k : format = 52 s / mount = 71 s
> block size 16k : format = 30 s / mount = 36 s
> block size 32k : format = 18 s / mount = 19 s
>
> Using 4kB blocks makes mount too slow on the STB, which
> is why I'd like to use larger blocks. It would be nice
> if the movies recorded on the STB could also be read on
> a Linux PC.

Is there, perhaps, a better place to discuss this issue?

--
Regards, Mason