Filesystem question

[David Collier-Brown]

On Fri, 13 Oct 2000, David Collier-Brown wrote:
> > For big directories, yes. A mere 10,000 files/directory will drag
> > Solaris and Linux down significantly.

>James Sutherland wrote:
> You mean the linear search through a directory will slow Solaris
> down? If that's the problem, I don't think a Samba-side solution is the
> right one. Have you tried experimenting with Solaris directory caching??

	My caches are auto-growing properly, so they're ok.
	What I did try was logging (described earlier) which
	radically improved metadata update operations.

> In which case, why try to fix this issue in Samba? It's clearly a Solaris
> issue, IMO.

	As I said before, Solaris is slow because it has to
	be general.  Samba **can** be faster, because it can
	use the best algorithm for the specific operations
	it does.  That doesn't mean it will be: this will
	take some careful analysis and measurement of the
	directory operations in NetBench.

> I'd try adding the cache Solaris-side first: this should provide the same
> benefits, but avoid the issues raised earlier and benefit other
> applications too.

	That's been done: we just saw a 30-odd percent improvement
	in directory speed going to the next Solaris 8 quarterly
	CD. This will be continued by the filesystem group(s),
	driven by reports from the customers. 

	In the case of directory operations, this was driven by 
	customers using PC NetLink and Samba, who detected non-linear
	performance degradation on overloaded disks.  This produced poor
	results from smbtorture and NetBench (for all UFSs, actually).
	This will be of interest to the Linux ext2 folks, too, although
	they have quite a different algorithm...

--dave
-- 
David Collier-Brown,  | Always do right. This will gratify some people
185 Ellerslie Ave.,   | and astonish the rest.        -- Mark Twain
Willowdale, Ontario   | //www.oreilly.com/catalog/samba/author.html
Work: (905) 415-2849 Home: (416) 223-8968 Email: davecb at canada.sun.com