On 9/24/21 6:13 PM, 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?
Technically, should work fine.
Administratively? you got a mess on your hands.
With a fair amount of certainty, I can say you will run into at least
the following administrative problems:
* users added/changed to live box, not duplicated to spare.
* Updates done to live box, not to spare
* rule changes done to live box, not to spare.
* Other settings changed on live box, not duplicated to spare.
None of these are intrinsically CARP issues or solved by CARP at all
but all of them are are going to be complicated by having a machine that
is off when changes are made to the live one. All these issues have to
be considered with a CARP setup, but with a machine powered off, you KNOW
they won't be dealt with in a timely manner...which means they won't be
there when you need them.
If your goal is really to have one machine running, I'd suggest skipping
CARP, and just mirror the drives on the primary and keep spare hw in
reserve, and keep good backups of ALL configuration information. Drive
fails? you got a mirror. HW fails? you got spare, move the drives,
bring it up. Keep it simple, you will be happier.
Nick.
