file space question

Vulpes Velox kitbsdlist2 at
Wed Jun 2 11:09:50 PDT 2004

On Tue, 1 Jun 2004 16:23:20 +1000 (EST)
Bruce Evans <bde at> wrote:

> On Mon, 31 May 2004, Vulpes Velox wrote:
> > Does ufs have the same problem like FAT32, in that if a file
> > exists, it will all ways take up atleast 4KB or so, no matter how
> > little data it contains?
> Not exactly.   ufs has fragments, which normally have size 1/8 of
> the block size, so a 1 byte file normally only takes 1/8 of the
> block size. However, the default block size is 16K, so fragments
> usually take up at least 2K.  If nonstandard block and fragment
> sizes are used, then the minimum is the same for ufs and msdosfs:
> 	ufs: block size 4096, frag size 512
> 	msdosfs: block size 512
> With FAT32, 512-byte blocks can cover fairly large disks.  IIRC,
> there can be 2^28 clusters for FAT32, so the maximum is 2^28*512 =
> 128GB. The default block size for msdosfs originally grew large (up
> to 32K or 64K) back when there was only FAT16 and the limit was 2^16
> or 2^15 clusters.  2*16*32K is just 2GB, so even with the too-large
> block size of 32K wasn't large enough for new disks about 10 years
> ago.  Since then, 4K has become the default for most cases since it
> is a good i/o size(still a little too small, but OK with some
> buffering), and because using a reasonably large block size helps
> stops the FAT size from beoming preposterously large (2^28 clusters
> takes 1GB for the FAT).
> Also, msdosfs has much smaller metadata overheads than ufs, so it
> can hold a lot of small files in the space that ufs would use for
> metadata. The wastage is very noticable on small file systems like
> ones that fit on floppy disks.

So storing bookmarks and the like each in their own file, on UFS is a
bad idea then? Or given modern disk sizes probally can easily be

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