69 lines
2.7 KiB
Plaintext
69 lines
2.7 KiB
Plaintext
Desc: Typical setups for big servers
|
|
File: big-servers.txt
|
|
Date: 14 March 2004
|
|
Auth: Russell Kroll <rkroll@exploits.org>
|
|
|
|
By using multiple MONITOR statements in upsmon.conf, you can configure
|
|
an environment where a large machine with redundant power monitors
|
|
multiple separate UPSes. For the examples in this document, I will use
|
|
a HP NetServer LH4 in the stock configuration with 3 of the 4 power
|
|
supplies installed.
|
|
|
|
Compared to some systems, the LH4 is unusual because it has common power
|
|
cords for multiple power supplies. One cord feeds two supplies. As a
|
|
result, each UPS drives two of the power supplies, so losing that UPS
|
|
affects both at the same time.
|
|
|
|
For our examples, UPS "Alpha" is connected to the cord that drives the
|
|
two power supplies, and ups "Beta" is connected to the other with just a
|
|
single power supply.
|
|
|
|
Since the server needs two supplies to stay alive, we can lose "Beta" at
|
|
any time, but losing "Alpha" is a showstopper. We make a note of them
|
|
when configuring upsmon:
|
|
|
|
MONITOR ups-alpha@myhost 2 monuser mypass master
|
|
MONITOR ups-beta@myhost 1 monuser mypass master
|
|
MINSUPPLIES 2
|
|
|
|
With that configuration, upsmon will only shut down when Alpha reaches
|
|
a critical (on battery + low battery) condition, since Beta by itself
|
|
is not enough to keep the system running. Beta, on the other hand,
|
|
can go up and down as much as it wants and nothing will happen as long
|
|
as the other one keeps working.
|
|
|
|
The MINSUPPLIES line tells upsmon that we need at least 2 power supplies
|
|
to be receiving power from a good UPS (on line or on battery, just not
|
|
on battery and low battery).
|
|
|
|
Adding redundancy
|
|
=================
|
|
|
|
The above example assumed the stock hardware configuration. Let's say
|
|
we have successfully cajoled the boss into providing the money for a
|
|
fourth power supply. Now both power cords run two power supplies, and
|
|
the system is maxed out in terms of redundancy.
|
|
|
|
The upsmon.conf must be updated to reflect this:
|
|
|
|
MONITOR ups-alpha@myhost 2 monuser mypass master
|
|
MONITOR ups-beta@myhost 2 monuser mypass master
|
|
MINSUPPLIES 2
|
|
|
|
Beta is now driving two power supplies, so we upgrade its power value.
|
|
This means that either Alpha *or* Beta can totally shut down and the
|
|
server will be able to keep running.
|
|
|
|
As an added bonus, this means you can move a running server from one UPS
|
|
to another without bringing it down since the minimum power will be
|
|
provided at all times.
|
|
|
|
Other configurations
|
|
====================
|
|
|
|
There are a lot of ways to handle this and they all come down to how many
|
|
power supplies, power cords and independent UPS connections you have. A
|
|
system with a 1:1 cord:supply ratio has more wires stuffed behind it, but
|
|
it's much easier to move things around since any given UPS drives a smaller
|
|
percentage of the overall power.
|