Re: [9fans] fossil speed

[geoff@collyer.net]

It is possible to generate file server kernels exactly compatible with
existing ken fs on-disk file systems, but you get none of the benefits
of the new file server if you do that.  It does however let you build
old and new file server kernels from the same sources.

If you want to get the benefits of the new file server (64-bit file
sizes, offsets and block numbers; smarter IDE code ported from the cpu
kernel; larger file name components; indirect blocks beyond
double-indirect; etc.), you have to build a new file server kernel
that will not be compatible on disk with existing file systems (it
will however speak 9p2000 compatibly, though not 9p1, because 9p1
depends crucially on NAMELEN being 28; 9p1 is disabled in the new file
server kernels, but it turns out that nothing needs 9p1 any more [old
drawterm uses it, but it never connects to file servers directly]).

I decided that I could live without the history on my old file server,
so just copied its main file system to a new file server.  It's nice
to not need lnfs any more.