Re: Power and temperature

From: sujay gupta <>
Date: 02/15/10
Message-ID: <>


Agree, it does make sense to add counters carrying this energy/power
related information.

Assuming the target networks to monitor for power/energy measurements
are Data-Centers. A little digging would reveal that there is more
info besides the basic counters of KWhr & Temp which sFlow needs to
A typical Data-Center consisting of UPS, switches, routers, storage,
servers, base power meters has much more amount of information to be
"Smartmeters" carry at least these information;
(i) on-peak kWhr
(ii) off-peak kWhr
(iii) Time of Use(TOU)
(iv) Outage counts
(v) Voltage
(vi) Current
(vii) Polling frequency - (how frequently the volt/current is polled and stored)
( This is not a complete list but more or less sufficient, there are
quite a few IEC & ANSI specifications
which talk about accuracy, measurement and testing for the above)

On the device level, modern day Digital Power Controllers used in UPS,
power supply units in
routers, switches, storage measure and provide the following information;
( these are also often present in proprietary MIB's)
(i) overvoltage/undervoltage info - fault/warnings
(ii) overcurrent/undercurrent info -fault/warnings
(iii) overtemperature/undertemperature info -fault/warnings
(iv) fan fault
(v) manufacturer specific device error.
(vi) realtime(or almost) voltage
(vii) reatime (or almost) current
(viii) realtime( or almost) temperature- sub-unit wise
( Refer to PMbus specifications, )

Having said that, both the above lists are not complete but mostly
sufficient, IMO also there are no strict standards being followed
all across, it seems to be varying with country, vendor & their partners.

So, if sFlow were to carry power /energy information it should be
sub-set or a smart aggregation of them.

Another interesting point is the applications which monitor the above
not only give gross-data,sometimes they also provide fault
prediction.(that gives a perspective into the type of data sFlow
should mine)


On Tue, Jan 5, 2010 at 5:03 PM, Peter Phaal <> wrote:
> Power management is an increasingly important consideration in managing networks.
> Adding sFlow counters to allow agents to report on power and temperature would provide useful information for power optimization.
> /* Energy consumption */
> /* opaque = counter_data; enterprise = 0; format = 3000 */
> struct energy {
> unsigned hyper mJ; /* energy in millijoules */
> unsigned int pf; /* power factor (expressed as a percent), 0 for DC power */
> }
> /* Temperature */
> /* opaque = counter_data; enterprise = 0; format = 3001 */
> struct temperature {
> int oC<>; /* array of temperatures (1 for each thermometer) expressed in degrees Celsius */
> }
> Each measurement is scoped by the data source reporting it. In the case of energy, a switch might report total energy for the whole box (as measured by its power supply) and may also report energy for each of its PoE ports.
> Adding these counters to sFlow (currently contained in proprietary SNMP MIBs if available at all) would provide an efficient, multi-vendor way to track power usage and temperature across all the devices and links in the network. SFlow counter polling is very efficient, providing a scalable way to monitor the large numbers of devices in a data center.
> Peter
Received on Mon Feb 15 20:58:08 2010

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