What is fragment in ext3/4 ?
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These days, when I read the source code of mke2fs, I found an option -f to set the fragment size.
But I can not find any explaining for ext3/4 framgment from google, excepting someone saying ext2/3 does not support this feature.
Can anyone tell me what is the function or purpose of fragment of ext file system ?
Thanks in advance :-)
Coly
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Quoted 8 lines · Coly Li
These days, when I read the source code of mke2fs, I found an option -f to set the fragment size.
But I can not find any explaining for ext3/4 framgment from google, excepting someone saying ext2/3 does not support this feature.
Can anyone tell me what is the function or purpose of fragment of ext file system ?
This is an obsolete concept from BSD that was never used by ext[234]. Consider a "fragment" in this context to be the same as a "tail" for reiserfs. A very small file, or the end of a file that is less than a block.
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
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I read from manual and source code, it seems fragment size should be same to filesystem block size. Therefore, can I say current ext3/4 filesystem still do not support fragment ?
Thanks.
Coly
Quoted 15 lines · Andreas Dilger
Quoted 8 lines · Coly Li
These days, when I read the source code of mke2fs, I found an option -f to set the fragment size.
But I can not find any explaining for ext3/4 framgment from google, excepting someone saying ext2/3 does not support this feature.
Can anyone tell me what is the function or purpose of fragment of ext file system ?
This is an obsolete concept from BSD that was never used by ext[234]. Consider a "fragment" in this context to be the same as a "tail" for reiserfs. A very small file, or the end of a file that is less than a block.
Quoted 6 lines
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
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Quoted 7 lines · Andreas Dilger
Quoted 6 lines · Coly Li
These days, when I read the source code of mke2fs, I found an option -f to set the fragment size.
But I can not find any explaining for ext3/4 framgment from google, excepting someone saying ext2/3 does not support this feature.
Quoted 7 lines
Quoted 2 lines
Can anyone tell me what is the function or purpose of fragment of ext file system ?
This is an obsolete concept from BSD that was never used by ext[234]. Consider a "fragment" in this context to be the same as a "tail" for reiserfs. A very small file, or the end of a file that is less than a block.
There's a fair amount of code around this never-implemented concept; should it be removed? :)
-Eric
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Quoted 10 lines · Eric Sandeen
Quoted 9 lines · Andreas Dilger
Quoted 8 lines · Coly Li
These days, when I read the source code of mke2fs, I found an option -f to set the fragment size.
But I can not find any explaining for ext3/4 framgment from google, excepting someone saying ext2/3 does not support this feature.
Can anyone tell me what is the function or purpose of fragment of ext file system ?
Quoted 7 lines
Quoted 4 lines
This is an obsolete concept from BSD that was never used by ext[234]. Consider a "fragment" in this context to be the same as a "tail" for reiserfs. A very small file, or the end of a file that is less than a block.
There's a fair amount of code around this never-implemented concept; should it be removed? :)
I agree with this idea. It seems we will never implement it in future, once "fragment" packed into inode.
Coly
Quoted 3 lines
-Eric
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Quoted 7 lines · Coly Li
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Quoted 2 lines · Eric Sandeen
There's a fair amount of code around this never-implemented concept; should it be removed? :)
I agree with this idea. It seems we will never implement it in future, once "fragment" packed into inode.
Yes, this should all be removed. In fact, the "fragment" fields are being reassigned in the upstream e2fsprogs, so there is no chance to implement it in the future either. If we ever want to have fragments like this, the plan was to add them as EAs in the inode (no point to make an external EA block to hold a block of data).
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.