bde at zeta.org.au
Wed Nov 2 06:18:00 PST 2005
On Tue, 1 Nov 2005, Ivan Voras wrote:
> On Tue, 1 Nov 2005, Bruce Evans wrote:
>> On Mon, 31 Oct 2005, Ivan Voras wrote:
> [for ext2fs under FreeBSD]
>> first few cylinder groups full and the rest unused, where Linux would
>> use all the groups fairly evenly.
> Not so good. I suppose this is not easaly fixable?
Not very easily, but not very uneasily either. We can either obtain
a block allocator from NetBSD (I think it is similar to ffs's, but
specialized to ext2fs), or use the current Linux allocator (I think
we have an old version already -- ISTR a comment saying that it is
used for checking only).
>> - ext2fs is about twice as slow as the other 2 (worse for non-async
>> It is mostly because the block size is very small, and although this
>> only necessarily costs extra CPU to do clustering, FreeBSD is optimized
>> for ffs's default block size and does pessimal things with ext2fs's
>> smaller sizes.
> These effects are also very noticable with NTFS (default block size=4096 for
> all/most partition sizes) and FAT32 on smaller drives (where bs=4096 fits FAT
> in 8MB).
4K isn't too bad, except possibly on arches with a page size of 8K -- see
my benchmark output for msdosfs. Clustering is certainly required to
get good results for large files.
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