CentOS - Jan 2006 - Ext3 filesystem access after downgrade from v4.2 to v3.6

I need to downgrade a system from Centos x4.2 to v3.6 (x86) due to
performance problems with Arkeia Network Backup and AIT-4 tape drives.
The backup database is stored on a v4.2 created ext3 partition. When
accessing this partition after the downgrade, Centos complains on boot
that

fsck.ext3: Filesystem has unsupported feature(s) (/dev/sda5)
*fsck: Get a newer version of e2fsck! [fail]

If I comment the partition out of /etc/fstab the machine boots as normal
and I can manually mount the filesystem.

My questions are:

If I use the v4.2 ext3 filesystem on v3.6 I am likely to corrupt the
data? And what is the best way fix this problem? Do as it says and try
and upgrade e2fsck or is there a better fix?

Thanks

Dean.

On Monday 23 January 2006 16:46, Plant, Dean wrote:
> I need to downgrade a system from Centos x4.2 to v3.6 (x86) due to
> performance problems with Arkeia Network Backup and AIT-4 tape drives.
> The backup database is stored on a v4.2 created ext3 partition. When
> accessing this partition after the downgrade, Centos complains on boot
> that
>
> fsck.ext3: Filesystem has unsupported feature(s) (/dev/sda5)
> *fsck: Get a newer version of e2fsck! [fail]
you can list the features with the command "tune2fs -l /dev/sda5" and
toggle
features too (read the man page). It's most likely the dir_index feature...
>
> If I comment the partition out of /etc/fstab the machine boots as normal
> and I can manually mount the filesystem.
>
> My questions are:
>
> If I use the v4.2 ext3 filesystem on v3.6 I am likely to corrupt the
> data?
I don't think you're running any risk of corrupting your data.

/Peter
> And what is the best way fix this problem? Do as it says and try 
> and upgrade e2fsck or is there a better fix?
>
> Thanks
>
> Dean.
-- 
------------------------------------------------------------
  Peter Kjellstr?m               |
  National Supercomputer Centre  |
  Sweden                         | http://www.nsc.liu.se
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RedHat had modified some specification of ext2 by patching to e2fsprogs
arbitrarily. So the ext2 on EL4 is not used to be. 

If you make filesystems on EL4, you have no way to mount them on EL3.
Of course, you can do it after mke2fs on EL3 again.
Necessarily, Cent 4.x is polluted by it. ;)
 
> I need to downgrade a system from Centos x4.2 to v3.6 (x86) due to
> performance problems with Arkeia Network Backup and AIT-4 tape drives.
> The backup database is stored on a v4.2 created ext3 partition. When
> accessing this partition after the downgrade, Centos complains on boot
> that
>
> fsck.ext3: Filesystem has unsupported feature(s) (/dev/sda5)
> *fsck: Get a newer version of e2fsck! [fail]
>
> If I comment the partition out of /etc/fstab the machine boots as normal
> and I can manually mount the filesystem.
>
> My questions are:
>
> If I use the v4.2 ext3 filesystem on v3.6 I am likely to corrupt the
> data? And what is the best way fix this problem? Do as it says and try
> and upgrade e2fsck or is there a better fix?
>
> Thanks
>
> Dean.
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