Re: [RFC 0/13] extents and 48bit ext3

Mingming Cao
2006-06-09T15:23:15Z

Valdis.Kletnieks@vt.edu wrote:
> On Thu, 08 Jun 2006 18:20:54 PDT, Mingming Cao said:
>
>>Current ext3 filesystem is limited to 8TB(4k block size), this is
>>practically not enough for the increasing need of bigger storage as
>>disks in a few years (or even now).
>>
>>To address this need, there are co-effort from RedHat, ClusterFS, IBM
>>and BULL to move ext3 from 32 bit filesystem to 48 bit filesystem,
>>expanding ext3 filesystem limit from 8TB today to 1024 PB. The 48 bit
>>ext3 is build on top of extent map changes for ext3, originally from
>>Alex Tomas. In short, the new ext3 on-disk extents format is:
>
>
> which implies matching changes to mkfs.ext2 and possibly mount..
>
>
Alexandre Ratchov and Laurent Vivier from BULL have been done some work
in e2fsprog to support extents and 48/64 bit ext3, although the patches
have not been thoroughly reviewed and discussed yet...

http://marc.theaimsgroup.com/?l=ext2-devel&m=114848122624510&w=2

>>Appreciate any comments and feedbacks!
>
>
> Somebody else was recently discussing a set of patches to ext3 for
> extents+delalloc+mballoc patches - is this work compatible with that?
>
Yes, the extents patch you mentioned is the same one included in the
series. The delalloc (support delayed allocation for ext3) and mballoc (
support multiple block allocation based on extents) are considered a
future to add, as this series is intend to address the capability issue
and on-disk format only.

> Also, a pointer to the matching userspace patches would help anybody
> who's gung-ho enough to test the code....
>

Thanks for your interest!

We have tested patch 1-4 (which basically not touching any on-disk
format) and they have been in mm tree. Extent patch itself have been
tested for a long time by ClusterFS and IBM, as it's actually being
posted a while back.

At this point the whole series pass compile, but not being tested yet.
This post as a RFC is intend to collect comments and feedbacks. BULL
team has done some test on the 2.6.16 version of the series with the
e2fsprog changes they posted though. I will upload the matching
e2fsprogs changes to ext2.sf.net/48bitsext3 shortly..

Mingming