Date: Tue, 24 Apr 2018 14:27:38 +0300 From: Mikhail Zakharov <zmey20000@yahoo.com> To: karli@inparadise.se Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: ctl_isc_lun_sync: Received conflicting HA LUN Message-ID: <56E4773F-4EAD-47EB-A803-38BFCD8C63F8@yahoo.com> In-Reply-To: <1524567842.9560.66.camel@inparadise.se> References: <4cb4aa83-bd49-0c20-4e41-c11c682b0570@sentex.net> <F908B78A-DD9B-4204-BA1E-24CE38059ACF@yahoo.com> <1e1e7cd5-0797-c168-fbce-a36edc6a432e@sentex.net> <1524550160.1130.6.camel@inparadise.se> <615DFFBB-239A-4350-B961-FD10D0C9A8DD@yahoo.com> <1524567621.9560.65.camel@inparadise.se> <1524567842.9560.66.camel@inparadise.se>
next in thread | previous in thread | raw e-mail | index | archive | help
Ah, and unfortunately CTL HA is two-node cluster, as I remember, there is no possibility to add the third one. So the third node is an external arbiter in that case. > 24 апр. 2018 г., в 14:04, Karli Sjöberg <karli@inparadise.se> написал(а): > >> On Tue, 2018-04-24 at 13:00 +0200, Karli Sjöberg via freebsd-fs wrote: >>> On Tue, 2018-04-24 at 12:32 +0300, Mikhail Zakharov wrote: >>> Hi Karli, >>> >>> Thank you, I’m just exploring the storage abilities of my preferred >>> OS - FreeBSD. >>> >>> Three nodes are preferable to choose the quorum for sure, but my >>> idea >>> was not to establish contacts between nodes. Instead of it, BQ uses >>> a >>> small partition for the “quorum” on the same space where data >>> volume >>> is located. >> >> Yes, of course. But there´s nothing you from having three nodes > > 's/nothing you/nothing stopping you/' > >> connected to the same partition and being able to make more accurate >> choices on when to take over? >> >> If one node stops updating stamps, take over. If two nodes stops >> updating, then the problem is likely network-related and _must not_ >> take over to avoid split brain. Something like that? >> >> /K >> >>> And if a node looses access to the quorum it means, it looses >>> access >>> to the data volume too. Now, BQ runs on both nodes and both BQ >>> instances write stamps to the quorum partition. If for any reason >>> BQ >>> on one node detects, the other node stops updating it’s stamps, it >>> performs failover procedure. It’s quite a questionable, rude way, I >>> can agree, and that’s why I always write a warning to use the BeaST >>> for testing only purposes. >>> >>> Best regards, >>> Mike >>> >>>> 24 апр. 2018 г., в 9:09, Karli Sjöberg <karli@inparadise.se> >>>> написал(а): >>>> >>>>>> On Mon, 2018-04-23 at 13:11 -0400, Mike Tancsa wrote: >>>>>> On 4/23/2018 12:59 PM, Mikhail Zakharov wrote: >>>>>> >>>>>> Hello Mike, >>>>>> >>>>>> Thank you for your interest to my paper. I appreciate it very >>>>>> much! >>>>>> Your error may be a consequence of the initial HA >>>>>> misconfiguration. >>>>>> What is in your /boot/loader.conf? Although the described >>>>>> config is >>>>>> quite simple, I can recheck the instruction in my paper in a >>>>>> couple >>>>>> of weeks only, unfortunately I’m on vacation right now. >>>> >>>> [snip] >>>> >>>> I read your articles on CTL HA, BQ and BeaST, and just wanted to >>>> say >>>> they are amazing, good job! >>>> >>>> One thing I´m wondering about though is if you can claim HA with >>>> just >>>> two nodes, usually you need at least three, where the third is a >>>> tie- >>>> breaker. Otherwise with your current setup, both systems may >>>> loose >>>> contact with each other while both still being powered on, >>>> leading >>>> to >>>> potential split brain situations. What are your thoughts about >>>> that? >>>> >>>> /K
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?56E4773F-4EAD-47EB-A803-38BFCD8C63F8>