On 2013-03-16 15:20, Bob Friesenhahn wrote:
On Sat, 16 Mar 2013, Kristoffer Sheather @ CloudCentral wrote:

Well, off the top of my head:

2 x Storage Heads, 4 x 10G, 256G RAM, 2 x Intel E5 CPU's
8 x 60-Bay JBOD's with 60 x 4TB SAS drives
RAIDZ2 stripe over the 8 x JBOD's

That should fit within 1 rack comfortably and provide 1 PB storage..

What does one do for power?  What are the power requirements when the
system is first powered on?  Can drive spin-up be staggered between JBOD
chassis?  Does the server need to be powered up last so that it does not
time out on the zfs import?

Giving this question a second thought, I think JBODs should spin-up
quickly (i.e. when power is given) while the server head(s) take time
to pass POST, initialize their HBAs and other stuff. Booting 8 JBODs,
one every 15 seconds to complete a typical spin-up power draw, would
take a couple of minutes. It is likely that a server booted along with
the first JBOD won't get to importing the pool this quickly ;)

Anyhow, with such a system attention should be given to redundant power
and cooling, including redundant UPSes preferably fed from different
power lines going into the room.

This does not seem like a fantastic power sucker, however. 480 drives at 15W would consume 7200W; add a bit for processor/RAM heads (perhaps
a kW?) and this would still fit into 8-10kW, so a couple of 15kVA UPSes
(or more smaller ones) should suffice including redundancy. This might
overall exceed a rack in size though. But for power/cooling this seems
like a standard figure for a 42U rack or just a bit more.


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