> Next3 transactions reserve up to 24 times more credits than Ext3 transactions for the same operation. On mke2fs and tune2fs, if the 'big_journal' feature is set along with the 'has_journal' feature, increase the default journal size by a factor of 24.
It is already possible to specify an arbitrary journal size with "-J size={MB}", so there is no need to consume a feature flag just to hint what the journal size should be.
It would be possible to check for some other snapshot-related feature flag, like "EXCLUDE_INODE" to determine if the journal is large enough for snapshotting, if it was deleted by e2fsck. Otherwise, it is best to let the user specify the journal size they want.
Cheers, Andreas
On Mon, Jun 21, 2010 at 9:21 PM, Andreas Dilger <[email protected]> wrote:
>> Next3 transactions reserve up to 24 times more credits than Ext3 transactions for the same operation. ?On mke2fs and tune2fs, if the 'big_journal' feature is set along with the 'has_journal' feature, increase the default journal size by a factor of 24.
>
> It is already possible to specify an arbitrary journal size with "-J size={MB}", so there is no need to consume a feature flag just to hint what the journal size should be.
>
> It would be possible to check for some other snapshot-related feature flag, like "EXCLUDE_INODE" to determine if the journal is large enough for snapshotting, if it was deleted by e2fsck. ?Otherwise, it is best to let the user specify the journal size they want.
>
Ted has already pointed out that a -J option would be more appropriate for this,
so I implemented the -J big option instead of the big_journal feature.
The differences between -J size={MB} and -J big, are:
1. -J big is more user friendly
2. -J big chooses a size which is the best fit for the file system size
BTW, those are not the most recent patches. the latest patch series is
available at:
http://sourceforge.net/projects/next3/files/Latest%20patch%20series
If you like, I can post the latest patches to the list.
Amir.