Date: Thu, 28 Jan 2021 16:11:50 -0800 From: John-Mark Gurney <jmg@funkthat.com> To: Willem Jan Withagen <wjw@digiware.nl> Cc: Matt Churchyard <matt.churchyard@userve.net>, "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org> Subject: Re: Warm Migration feature for bhyve - review on Phabricator Message-ID: <20210129001150.GR31099@funkthat.com> In-Reply-To: <5c6ff016-e15d-afad-e855-8cfed32276f2@digiware.nl> References: <CAGOCPLhP3i4hPcKHX=RrKFbQiSenjtJrvzTx%2BARnP8=QN%2BzmqQ@mail.gmail.com> <e9a65e1ad4e0491083820fbb03d873e8@SERVER.ad.usd-group.com> <20210125062113.GL31099@funkthat.com> <7769d16522fa49558049f4a6e936982e@SERVER.ad.usd-group.com> <20210125184204.GM31099@funkthat.com> <5c6ff016-e15d-afad-e855-8cfed32276f2@digiware.nl>
next in thread | previous in thread | raw e-mail | index | archive | help
Willem Jan Withagen wrote this message on Thu, Jan 28, 2021 at 01:42 +0100:
> On 25-1-2021 19:42, John-Mark Gurney wrote:
> > Matt Churchyard wrote this message on Mon, Jan 25, 2021 at 10:46 +0000:
> >> -----Original Message-----
> >> From: John-Mark Gurney <jmg@funkthat.com>
> >> Sent: 25 January 2021 06:21
> >> To: Matt Churchyard <matt.churchyard@userve.net>
> >> Cc: Elena Mihailescu <elenamihailescu22@gmail.com>; freebsd-virtualization@freebsd.org
> >> Subject: Re: Warm Migration feature for bhyve - review on Phabricator
> >>
> >>> There's also hastd which can aid with this...
> >> Thanks for the reply. I've always been wary of the additional complexity of HAST and ZFS, as it doesn't seem to have widespread usage or support, and things get ugly fast when storage is involved.
> > Totally agree...
> >
> >> However, the idea of using HAST on top of zvols to provide network mirrored storage for a guest is interesting. It adds a lot of extra complexity, and probably performance impact though if it's just for the ability to move a guest between systems that may only happen every now and then. I'm also not sure it would help (or would at least be even more complex) if I have 4 hosts and want to be able to move guests anywhere.
> > gmirror + ggate is another option as well...
>
> I did try all kinds of these solutions that are based on a 2 system
> backend storage, and it was relatively easy for me to get the state of
> the storage in a split-brain situation which is not really repairable
> without a lot of manual user intervention.
> So I gave up on HAST and gmirror over ggate.
Can you explain more about the split brain w/ gmirror+ggate? If writes
didn't happen to one of the members of gmirror, then that should be
investigated.. I guess I could see a situation where ggate got behind
on writes (connection drop), and gmirror didn't kick out the ggate
member, or failed to mark it as stale, but those are bugs that need
to be identified and fixed...
I'm partly currious about the ggate, because I've recently done some
work w/ ggate (performance improvements and working of sftp), and it's
simple enough that issues are a bit surprising..
I'm not at all familar w/ HAST to advice on any issues w/ that...
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20210129001150.GR31099>