J. Roeleveld:
> On Friday 20 November 2009 13:42:58 Arora, Sumit wrote:
> > Hi folks,
> >
> > I'm just testing my postfix server for load and disk usage.
> > I'm using content filter on some another server, and I don't feed the email
> > back to postfix.
> >
> > Email data is getting deleted from my postfix server, but I don't know
> > where 4KB of my disk space gone on every email my postfix server receives.
> > If anybody have some idea, please tell me.
> >
> > -Sumit Arora
> >
>
> My guess is that the filesystem has a block-size of 4KB.
>
> A file is stored over a set of blocks of this size. Which means
> that if a file is smaller then 4KB, it will still use a 4KB block.
>
> As far as I know, only reiserfs has the "notail"option which will
> try to stick multiple smaller files into a single block.
25 Years ago, the UFS file system came with large blocks (typ 8k)
and small fragments (typ 1k). The "tail fragments" from different
files could then share the same large block. In the mean time,
the 8k blocksize has been replaced by larger blocksizes like 32k
but the idea is the same: low fragmentation without wasting space.
Wietse
Marshall Kirk McKusick, William N. Joy, Samuel J. Leffler and Robert
S. Fabry. A Fast File System for UNIX. Technical Report Computer
Systems Research Group, Computer Science Division, Department of
Electrical Engineering and Computer Science, University of California,
Berkeley, Berkeley, CA 94720.
http://www.cs.berkeley.edu/~brewer/cs262/FFS.pdf
