[186062] in North American Network Operators' Group
Re: Rack Locks
daemon@ATHENA.MIT.EDU (Bob Purdon)
Tue Nov 24 23:11:56 2015
X-Original-To: nanog@nanog.org
Date: Wed, 25 Nov 2015 13:21:49 +1100
From: "Bob Purdon" <bobp@purdon.id.au>
To: "Bevan Slattery" <bevan@slattery.net.au>, "Jimmy Hess" <mysidia@gmail.com>,
"Kevin Burke" <kburke@burlingtontelecom.com>
In-Reply-To: <D276494A.4F989%bevan@slattery.net.au>
Cc: Kurt Kraut via NANOG <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
So what did we do. I used to use a relay type system in 2007-10 in my
previous data centre life. It=C2=B9s pretty good but a bit =C2=B3industrial=
=C2=B2. It=C2=B9s
also so 2007 (even 1990) and doesn=C2=B9t scale well when you are trying to=
do
3,000 racks and 6,000 doors per facility.
Part of the scaling issue was the door locks on that system were convention=
al solenoids, which from memory needed about 1A @ 12VDC to fire. =C2=A0If a=
customer had 30-40 racks (and a couple did in that facility), you'd need t=
o potentially fire 60-80 doors, or need 60-80 amps available (I have a reco=
llection we used a 12V SLA battery to ride out those peaks). =C2=A0Addition=
ally, monitoring lock status would have needed separate wiring and separate=
inputs. =C2=A0Cabling was a star topology (each rack directly back to the =
controller).
The TZ locks use a fraction of that power - from memory, only a few amps to=
do a pod of 30 or so racks. =C2=A0Firing a lock is measured in milliamps, =
not amps. =C2=A0The locks are controlled over RS485, so you get lock contro=
l and monitoring over a single cat-5. =C2=A0From memory the cable topology =
is technically hierarchical, but you could loosely consider it to be a bus.=
=C2=A0Overall, vastly superior to the 'industrial' style system.
I looked at the APC electronic
locking system, but the big issue is that some fool in product decided to
remove radius authentication, allowing a decent independent
command/control capability.
At the time the available version of the product didn't deal with too many =
racks, which also meant a lot of under-floor power outlets to feed the cont=
rollers). =C2=A0I think they were coming up with a denser version, but I di=
dn't see it.
