Date: Thu, 4 Mar 2010 09:27:19 +0200 From: Nikolay Denev <ndenev@gmail.com> To: Freddie Cash <fjwcash@gmail.com> Cc: fs@freebsd.org Subject: Re: PoC: ZFS fail-over with HAST + carp(4) + devd Message-ID: <7C1E347F-CD36-4F54-814B-90BE4EB67C75@gmail.com> In-Reply-To: <b269bc571003030913u3987c7dfre51fd7860b89f7e4@mail.gmail.com> References: <b269bc571003030913u3987c7dfre51fd7860b89f7e4@mail.gmail.com>
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On Mar 3, 2010, at 7:13 PM, Freddie Cash wrote:
> [Not sure if this should go to just fs@ or possibly current@ as well. =
I'll
> start with just fs@.]
>=20
> Thought I'd pass this along. It's a proof-of-concept setup I've been =
using
> to test HAST fail-over of a ZFS pool, using devd and carp(4). The =
original
> impetus for doing this was that ucarp doesn't work (for me) within a
> VirtualBox VM. Just hangs the VM. And, I prefer to use FreeBSD base =
tools
> whenever possible, so I thought I'd try and get it to work with =
carp(4).
>=20
> I know this isn't perfect as it (currently) relies on a "magic =
constant" and
> doesn't cover all the possible failure modes, but thought I'd pass it =
along
> to get your input, comments, criticisms, suggestions, etc. With a bit =
more
> work, it could be generalised a bit more to, for example, pull the =
resources
> list from /etc/hast.conf, and to work with non-ZFS setups. Perhaps =
someday
> it could be useful an an example in the HAST samples/ directory.?.
>=20
> With this setup, I can pull the plug on carp0 on the master node, and =
the
> hast devices and ZFS pool fail-over to the slave. And if I pull the =
plug on
> carp0 on the slave, everything fails over to the master again. And it =
works
> nicely with carp preempt enabled on the master node.
>=20
>=20
> Add the following stanzas to /etc/devd.conf:
> notify 10 {
> match "system" "IFNET";
> match "subsystem" "carp0";
> match "type" "LINK_UP";
> action "/usr/local/bin/carp-hast-switch =
master";
> };
>=20
> notify 10 {
> match "system" "IFNET";
> match "subsystem" "carp0";
> match "type" "LINK_DOWN";
> action "/usr/local/bin/carp-hast-switch =
slave";
> };
>=20
>=20
Hi,
It's a bit offtopic for fs-, but I'm just curious what FreeBSD version =
are you using with this?
My experience with 7.* is that LINK_UP/DOWN events are not generated for =
carp interfaces,
and I have just tested this in my devd.conf and it does nothing. I guess =
this is fixed in 8 or -CURRENT?
Regards,
Niki Denev=
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