Date: Tue, 24 Apr 2018 17:45:21 +0200 From: =?ISO-8859-1?Q?Karli_Sj=F6berg?= <karli@inparadise.se> To: Mikhail Zakharov <zmey20000@yahoo.com> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: ctl_isc_lun_sync: Received conflicting HA LUN Message-ID: <ECB3592B-B5FF-4CE2-A290-3DF96EBE0AA5@inparadise.se> In-Reply-To: <56E4773F-4EAD-47EB-A803-38BFCD8C63F8@yahoo.com> 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> <56E4773F-4EAD-47EB-A803-38BFCD8C63F8@yahoo.com>
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Mikhail Zakharov <zmey20000@yahoo=2Ecom> skrev: (24 april 2018 13:27:38 CE= ST) >Ah, and unfortunately CTL HA is two-node cluster, as I remember, there >is no possibility to add the third one=2E So the third node is an >external arbiter in that case=2E Yes, Arbiter, exactly the term I was looking for:) So it would be up to th= e Arbiter to decide whether it really is a node problem or a network proble= m- a tie-breaker=2E Would that be feasible in your software? /K > > >> 24 =D0=B0=D0=BF=D1=80=2E 2018 =D0=B3=2E, =D0=B2 14:04, Karli Sj=C3=B6be= rg <karli@inparadise=2Ese> >=D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB(=D0=B0): >>=20 >>> On Tue, 2018-04-24 at 13:00 +0200, Karli Sj=C3=B6berg via freebsd-fs >wrote: >>>> On Tue, 2018-04-24 at 12:32 +0300, Mikhail Zakharov wrote: >>>> Hi Karli, >>>>=20 >>>> Thank you, I=E2=80=99m just exploring the storage abilities of my pre= ferred >>>> OS - FreeBSD=2E=20 >>>>=20 >>>> Three nodes are preferable to choose the quorum for sure, but my >>>> idea >>>> was not to establish contacts between nodes=2E Instead of it, BQ uses >>>> a >>>> small partition for the =E2=80=9Cquorum=E2=80=9D on the same space wh= ere data >>>> volume >>>> is located=2E=20 >>>=20 >>> Yes, of course=2E But there=C2=B4s nothing you from having three nodes >>=20 >> 's/nothing you/nothing stopping you/' >>=20 >>> connected to the same partition and being able to make more accurate >>> choices on when to take over? >>>=20 >>> If one node stops updating stamps, take over=2E If two nodes stops >>> updating, then the problem is likely network-related and _must not_ >>> take over to avoid split brain=2E Something like that? >>>=20 >>> /K >>>=20 >>>> And if a node looses access to the quorum it means, it looses >>>> access >>>> to the data volume too=2E Now, BQ runs on both nodes and both BQ >>>> instances write stamps to the quorum partition=2E If for any reason >>>> BQ >>>> on one node detects, the other node stops updating it=E2=80=99s stamp= s, it >>>> performs failover procedure=2E It=E2=80=99s quite a questionable, rud= e way, I >>>> can agree, and that=E2=80=99s why I always write a warning to use the= BeaST >>>> for testing only purposes=2E=20 >>>>=20 >>>> Best regards, >>>> Mike >>>>=20 >>>>> 24 =D0=B0=D0=BF=D1=80=2E 2018 =D0=B3=2E, =D0=B2 9:09, Karli Sj=C3=B6= berg <karli@inparadise=2Ese> >>>>> =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB(=D0=B0): >>>>>=20 >>>>>>> On Mon, 2018-04-23 at 13:11 -0400, Mike Tancsa wrote: >>>>>>> On 4/23/2018 12:59 PM, Mikhail Zakharov wrote: >>>>>>>=20 >>>>>>> Hello Mike, >>>>>>>=20 >>>>>>> Thank you for your interest to my paper=2E I appreciate it very >>>>>>> much! >>>>>>> Your error may be a consequence of the initial HA >>>>>>> misconfiguration=2E >>>>>>> What is in your /boot/loader=2Econf? Although the described >>>>>>> config is >>>>>>> quite simple, I can recheck the instruction in my paper in a >>>>>>> couple >>>>>>> of weeks only, unfortunately I=E2=80=99m on vacation right now=2E >>>>>=20 >>>>> [snip] >>>>>=20 >>>>> I read your articles on CTL HA, BQ and BeaST, and just wanted to >>>>> say >>>>> they are amazing, good job! >>>>>=20 >>>>> One thing I=C2=B4m wondering about though is if you can claim HA wit= h >>>>> just >>>>> two nodes, usually you need at least three, where the third is a >>>>> tie- >>>>> breaker=2E 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=2E What are your thoughts about >>>>> that? >>>>>=20 >>>>> /K --=20 Skickat fr=C3=A5n min Android-enhet med K-9 Mail=2E Urs=C3=A4kta min f=C3= =A5ordighet=2E
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