From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryan O'Hara Date: Mon, 3 Aug 2009 11:19:44 -0500 Subject: [Cluster-devel] fence_scsi - Configuration file In-Reply-To: <4A77035F.60209@redhat.com> References: <4A71A96C.6080804@redhat.com> <20090803151402.GB26317@redhat.com> <4A77035F.60209@redhat.com> Message-ID: <20090803161944.GD26317@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Mon, Aug 03, 2009 at 05:33:51PM +0200, Jan Friesse wrote: > Ryan O'Hara napsal(a): >> What happens if we list devices and have auto_detect set to 'on'? Will >> we ignore the devices? With this auto_detect parameter, it seems that >> it will have to be explicitly set to 'off' and devices will have to be >> listed if we want to avoid auto-detect. Also, what happens if I set >> auto_detect to 'off' and I don't list any devices? >> > > autodetect set to "on" can have one of these two consequences: > - Ignore listed device - read only global sections for parameters ^^ I think this is the most logical thing to do. > - Ignore listed device but use per device parameters in case we will > find this device by old method - This is what is implemented now > - Use merge of listed devices and autodetected device > > autodetect is by default off. When we not have config file, it will > become on. When no devices is listed -> we turn it on Shouldn't auto_detect be default on? We want fence_scsi to work like it does now unless it is configured otherwise. I was thinking ... - If not config file exists, auto_detect is on. - If a config file does exists and auto_detect is not defined to be off, auto_detect should default to on ... regardless of whether or not any devices are listed. > I hope nobody will ever set autodetect to off and don't list any device, > but we can do two things: > - Ignore this flag and use vgs (this is what code does now) > - Do what user want -> no device fencing If this evern happens, the node will not register with any devices. There are two possible outcomes: 1. If a reservation already exists (being held by another node/key), the node in question won't have write access to the device(s) since it didn't register with anything. 2. If a reservation does not already exist, nothing changes and the node is completely unprotected and there is no way to fence it. I suppose there is a third case where the node is already registered, so doing nothing is valid, but this is just pure luck.