Filesystem question

James Sutherland jas88 at cam.ac.uk
Fri Oct 13 12:26:32 GMT 2000


On Fri, 13 Oct 2000, David Collier-Brown wrote:
> James Sutherland wrote:

> > Are cache hits really that slow in Solaris? :-)
> 
> For big directories, yes. A mere 10,000 files/directory will drag
> Solaris and Linux down significantly.

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??

> > Obviously there is some bottleneck here, but are you sure it lies in the
> > Samba<->Solaris interactions? 
> 
> No, I think they're almost all on my (Solaris) side of the interface.  
> Using smbclient get is only slightly slower than using cp.

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

> > The real question, though, is how much slower is extracting the data from
> > Solaris's cache as opposed to a Samba cache? Also, how much overhead will
> > the cache add to misses - think SparcStation 5 vs 10?
> 
> That's an open question: it's probbaly best discovered by observation
> and then an experiment, by adding a vfs with just a dir cache. (Tim
> Potter's vfs switch is a great help here).

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.


James.





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