Date: Thu, 29 Oct 2015 07:42:57 +0100 From: Ben RUBSON <ben.rubson@gmail.com> To: fs@freebsd.org Subject: Re: iSCSI/ZFS strangeness Message-ID: <B69E4406-8AD4-4249-87DB-F2DFCE9BB5C2@gmail.com> In-Reply-To: <B09FE8F0-F463-44C9-896C-CA55305113CE@nevada.net.nz> References: <20151029015721.GA95057@mail.michaelwlucas.com> <B09FE8F0-F463-44C9-896C-CA55305113CE@nevada.net.nz>
next in thread | previous in thread | raw e-mail | index | archive | help
> Le 29 oct. 2015 =C3=A0 03:26, Philip Murray <pmurray@nevada.net.nz> a = =C3=A9crit : >=20 >=20 >> On 29/10/2015, at 2:57 PM, Michael W. Lucas = <mwlucas@michaelwlucas.com> wrote: >>=20 >> Hi, >>=20 >> I'm experimenting with iSCSI HA with FreeBSD 10.2 amd64. I know = people >> do this sort of thing, but I can't figure out what I'm missing. (Most >> of the tutorials cover HAST instead). I suspect the real problem is >> "Lucas doesn't know the right search terms." >>=20 >> The goal is to make an iSCSI-based ZFS pool that's available to two >> separate hosts, and remains available even if one of the iSCSI = servers >> fails. Instead, the pool hangs when either of the iSCSI servers goes >> down. >=20 > I=E2=80=99m no expert and have never used iSCSI and FreeBSD before, = but I think you might=20 > want to look at the kern.iscsi.fail_on_disconnection sysctl. >=20 > man 4 iscsi >=20 > That means the devices will fail instead of hang, and ZFS might decide = to mark those=20 > devices as faulted instead of waiting for them to respond. Hi, Yes, kern.iscsi.fail_on_disconnection=3D1 in sysctl.conf will do the = trick. In addition, you can tune the following to minimize the impact / freeze = when iSCSI fails : kern.iscsi.ping_timeout=3D10 kern.iscsi.iscsid_timeout=3D10 kern.iscsi.login_timeout=3D10 In addition, in ctl.conf, perhaps you should use one target instruction = per disk. I began with all my disks/luns into a unique target configuration, but = when a disk fails and you replace it, you need to refresh the iSCSI = configuration using iscsictl -M. At this moment you will loose the = connection to all disks, leading into many ZFS devices failed... So I think a target per disks is better, then you only refresh the dead = target : iscsictl -M -i <the_target_session> And last thing, thank you very much for your quality books, a must-have = :) Best regards, Ben=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?B69E4406-8AD4-4249-87DB-F2DFCE9BB5C2>