Re: CARP Cold Spare

Unsure what the power draw is on these guys yet, they just got them. They have redundant 450W Platinum power supplies.

The "new" servers are completely overkill for the application, but this is a work-with-what's-available situation. They got these free from a friend and don't want to spend on new hardware, otherwise I'd just get them something "smaller" and supremely efficient.

We already have redundant UPS's. With the 3 servers previously (main VM servers and 1 now-dead firewall) attached to battery-backed power, we were getting roughly 3.5 hours of runtime before UPS drop. Sometimes minutes can matter with these blackouts.

I also want that with the one machine not running, it's not incurring any wear or tear just for the sake of hot failover.

I've got no talent on site, so in the event of a hardware or file system failure, It's an extremely tedious experience for me to walk someone there through swapping hardware, wiring, or reinstalling an operating system. So, I'm looking for that turn-this-one-off-and-this-one-on recovery option, without the need to fiddle with any hardware. If this works the way I want, the only single point of failure will be their cable modem, and Comcast can handle replacing that.

Option B is to just have identical configurations and have them need to swap the network wiring as part of the failover. Will still prevent the days of downtime we're incurring now due to this failure, but not as simple for them, if the CARP solution is solid.

> On Sep 25, 2021, at 10:25 AM, leonard <leonard@zaifman.ca> wrote:
>
> 
> What is the power draw? I use a 1500 VA apc backups with 6 outlets on ups and 5 on surge protection. As long as your total draw is less than 1200 VA, for < $200 canadian you have a cheap simple solution. Just put on on the ups side and the other on the surge suppressor side. Or buy 2.
>
>
>
> leonard@on the road
>
>
> -------- Original message --------
> From: Don Tek <dontek@gmail.com>
> Date: 2021-09-25 11:40 (GMT-05:00)
> To: jslee <indigoid@oldcorollas.org>
> Cc: misc@openbsd.org
> Subject: Re: CARP Cold Spare
>
> I'm not sure why the hardware matters, but the two machines are a couple HP 1U Gen 8 Xeon servers. Suffice to say, they are identical and have supported hardware configurations for OpenBSD.
>
> Of course I _could_ run one off direct power, but it would be a terrible idea. The location is notorious for power surges, blips that are enough to reboot servers and several-second brown-outs. So, not connected to the UPS is just asking for damages.
>
> They experience multi-hour blackouts what seems like once a month; this is where the desire to limit the draw on the UPS's comes from. To ensure we make it through without having to shut down.
>
> Remote access is of primary concern, both for me for support, since I'm geographically far enough away that being on-site is not feasible, and to the customer, who just wants to stay home and work on systems in the office.
>
> Configurations on the servers almost never change (simple firwall), so besides having to run a quick syspatch and reboot once at time of failover, I don't see maintenance being so bad. I keep config files backed-up otherwise centrally for quick restore to the running box as well.
>
> My primary concern here is if CARP / pfsync will have issues with the one machine being down a majority of the time. Based on the FAQ, I think not, but have no practical experience.
>
> > On Sep 25, 2021, at 3:00 AM, jslee <indigoid@oldcorollas.org> wrote:
> >
> > Hi,
> >
> > You haven't said anything about your hardware platform, but could you run one of them on non-UPS power? Then you'd still have one online when (*not* if) the UPS fails, and also they'll both normally be online for maintenance, syspatch, config changes etc
> >
> > I do recall installing a pair of identical servers at the same time and having them both fail a year later within an hour of each other, both with seized CPU fans, so I am somewhat sympathetic to your idea. But I think the practical cost of maintenance may be rather high
> >
> > John
> >
> >
> >> On Sat, 25 Sep 2021, at 08:13, Don Tek wrote:
> >> Would there be any 'problem' with configuring a 2-machine CARP setup
> >> and then just keeping one machine powered-off until needed?
> >>
> >> I realize this defeats live failover, but this is not a requirement for
> >> my customer.
> >>
> >> I just want them to be able to, in the event of a primary machine
> >> failure, power-on the secondary and have it take over. Logic here is
> >> to otherwise not have the secondary sucking power off the UPS's in the
> >> event of a power failure, or in general.
> >>
> >> Legit?
>