Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 21 Nov 2003 11:57:06 +1100
From:      Tim Robbins <tjr@freebsd.org>
To:        Alex Povolotsky <tarkhil@over.ru>
Cc:        fs@freebsd.org
Subject:   Re: "Reverse union" mount possible?
Message-ID:  <20031121005706.GA67377@wombat.robbins.dropbear.id.au>
In-Reply-To: <20031120144143.6cf73e06.tarkhil@over.ru>
References:  <20031120144143.6cf73e06.tarkhil@over.ru>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, Nov 20, 2003 at 02:41:43PM +0300, Alex Povolotsky wrote:

> Is it somehow possible, or how complex patch will require to get "reverse union"
> mount, with first lookup in underlying system, and file creation there as well?

I believe unionfs can do this (mount_unionfs -b option). mount's "union"
option only has a small subset of unionfs's features.

> Right now, I'm readonly mount_null'ing /bin, /sbin, /usr/bin, /usr/sbin,
> /usr/lib, /usr/include, /usr/libexec, /usr/share. With a dozen jails, there
> are too many mounts to my liking, and about twice a week I experience panic.
> Probabily it's nullfs-related.

Nullfs is known to be buggy in -stable. In particular, it seems to deadlock
under load / when vnodes start getting recycled.


Tim



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20031121005706.GA67377>