On 3 December 2013 22:45, David Laight <da...@l8s.co.uk> wrote: > On Tue, Nov 26, 2013 at 01:32:44PM -0500, Mouse wrote: >> >> When serving a request takes nontrivial time, and multiple requests can >> usefully be in progress at once, it is useful - it typically improves >> performance - to have multiple workers serving requests. NFS, as >> mentioned above, is a fairly good example (in these respects). > > Except that NFS is a bad example, and mostly should have a single server. > > If you could arrange a NFS server for each disk spindle you might win. > > But what tends to happen is that the disk 'elevator' algorithm makes > one of the server process wait ages for its disk access to complete, > by which time the client has timed out and resubmitted the RPC request. > The effect is that a slightly overloaded NFS server hits a catastrophic > overload and transfer rates become almost zero. > > Run a single nfsd and it all works much better.
On that basis should the NetBSD default be changed from -n 4?
