Kernel dumps [was Re: possible changes from Panzura]

[Ed Maste]

On 10 July 2013 19:07, Vincent Hoffman <vince at unsane.co.uk> wrote:
>
> There was some work on something similar at one point, not sure what
> came of it.
> http://lists.freebsd.org/pipermail/freebsd-current/2010-September/020164.html

The code referenced there has been used in production since 2005 or
so, and is based on an earlier implementation for FreeBSD 4.x that
dates to 2000.  Despite some shortcomings in the implementation it has
proved quite reliable in practice.

It hasn't made it into the tree yet for reasons raised in this thread.
 The primary issue is that it allocates mbufs in the packet sending
path, and so relies on a number of kernel subsystems to be in a
consistent state.  It doesn't use the stack, routing table, or driver
interrupt interfaces though.  It could likely be made committable with
a relatively small effort to switch to preallocating an mbuf+cluster
or two at configuration time.

More information is on the FreeBSD wiki, at https://wiki.freebsd.org/Netdump