Re: [9fans] Survey: Current Fossil+venti Filesystem

[David du Colombier <0intro@gmail.com>]

I ran dozens of file servers with only Fossil or both Fossil and Venti
since 2004, and I never lost any byte of data.

I experienced only few problems with Fossil. Most of them caused Fossil
to freeze or, more rarely, to crash.

In most cases, I simply rebooted the file server, and it worked fine
again.

What I can say is:

 - these problems tend to appear far much often when running on virtual
   machines like Qemu,
 - running Fossil without Venti prevent some problems, like freezes
   during snapshot to Venti.

I am currently running something like twenty file servers (including
standalone machines), from 8GB to 1.5TB of storage. Most file servers
are running Fossil with Venti, but some are only running Fossil.
I mirror Venti through network and regularly backup arenas to DVDs
(but I am recently moving to BD).

So far, I only succeeded to reproduce data-lost problems on Fossil when
running heavy stress testing.

I can understand Fossil have problems and they might cause data
corruption, but when data is archived to Venti, you can be sure it will
stay forever.

These problems with Fossil just have to be fixed. I am currently working
on a fossil derivative which use libventi and libthread instead of
liboventi and eventually fix these problems. I am already running it
on some test file servers, but it's too early to talk about experiences
with it.

--
David du Colombier