EMC CX300 and planned power loss

[ezhosting]

Hi, we was informed today that there will be some work with the power at where our ESX datacenter is set up, the work will take two hours, but the power is estimated to just be away two times at ten seconds each.

What I wonder then is if the SAN will shut it self down when it looses power for such a short amount of time?

It is connected with 1 cord directly from the power net, and one cord via the UPS that came with it.

Our ESX servers is powered by an UPS that will keep them up those 30 seconds..

Greetings

[atbnet]

We have a CX3-20, it should continue to be powered from the UPS while it looses power from the mains. Im assuming this is all setup correctley. If your not sure and can schedule downtime I would go for that. Make sure you have backups too before the power goes off. All kinds of strange things happen when power goes. If the power goes off longer than 30 secs and ends up being a day because there was an unforseen problem you will be scrabling to shutdown your SAN before your UPS goes!

Andy, VCP,

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[ezhosting]

Hi,

Thanks for your answer.

Sorry, I have given some wrong information, it is not a ups connected to the san, but the SPS i am reffering to.

The reason I am wondering is because of the data cable(serial cable) going from the SPS to the SAN.... Doesnt that give the san information that the power is lost and would initiate a halt?

In the documentation that came with the emc cx3000 it says that if you ever gonna turn your san off the correct way of doing it is to turn the power button that is on the SPS shipped with the san to off, and wait for two minutes..

[atbnet]

The serial cable from the UPS to the SAN, will tell the SAN that the UPS is nearly dead and initiate a shutdown of the SAN. This is uncleanley shut the SAN down. You should disconnect all servers, i.e. shutdown all ESX servers etc connected to the SAN first or at least shutdown all the VMs on that SAN, then shudown the SAN. Otherwise potentially you will get data corruption galore. If you turn the UPS off with no mains power it will shutdown the SAN but I am sure that will not properly close the connections and open files etc. If there is mains it should continue to function with a UPS failure, otherwise what the point in the dual power sources if its going to shut it down. You could never do maintenance on once of the supplies without shutting down the SAN.

Plan for the worst, when you dont the worst happens.

Andy, VCP,

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[ezhosting]

Hi,

Thanks again for the answer, I gave some wrong information earlier.

The electrician guys have promised it should max take 30 seconds each time, and I will be on site

One power supply on the san is connected to the mains, the other is connected through the SPS (not UPS, sorry), so what is needed is to add a connection to the UPS, should that be done to the power supply connected to the main, or should I add it before the SPS ?

[atbnet]

Is the mains dirty power? And the SPS meaning surge protected/filtered?

So at the minute there is no UPS connected direct to a PSU on the SAN or indirect (i.e. before the SPS)? You will need an electrician to put a UPS in with your SPS.

Andy, VMware Certified Professional (VCP),

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[atbnet]

Out of intrest what is the UPS you have? (make/model)

Is it a small mains powered UPS?

A single phase UPS?

Or a three phase UPS?

Andy, VMware Certified Professional (VCP),

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[ezhosting]

Hi,again

by "mains" i mean the power that goes straight into the SAN, infront of one of the SANs power supply there is a SPS, it stands for "Stand By Power Supply"

My power scheme now currently look like this:

---> 220v --> san power supply 1

---> 220v -->SPS -->san power supply 2

this is fetched from the dell site:

The benefits of cache vaulting

"Dell|EMC products employ a simpler, more reliable cache preservation scheme called cache vaulting

. In this scheme, a Dell|EMC standby power supply (SPS) keeps the

entire storage system powered until all cache data is stored safely on

disk, after which an orderly system shutdown is executed. This process

occurs within a matter of minutes and indefinitely protects the data,

regardless of the power outage duration."

I guess I should be adding the ups before the SPS.... looking like this "main power (220v)-> ups->sps---> san power supply)

The thing I am wondering about is if the power to the sps is lost for a little while, will it initate the shutdown, or will it wait for a while...

Greetings,

[atbnet]

Whatever that is SPS is, sounds only temporary and will shutdown the SAN while it commits cache to disk. Not what you want. If you can whack the SAN on a UPS on the mains that will be good, otherwise you may needs to shut it down for those two hours, teh 30secs will trigger a shutdown by the sounds of it. I will find out more info at work tommorrow if our SAN is similar. Im new to this SAN atm, I assume its simliar.

Andy, VMware Certified Professional (VCP),

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[ezhosting]

Thanks, I will call Dell tomorrow too and see if they have an answer for me! keep me updated if you find anything out.

thanks again

[HeadsUp]

anyone know if a SPS can be converted to a UPS ?

i have two EMC API 1FS18 standby power units , they are 1000 VA each , why cant they be converted to a UPS with that rating ?

there is an RJ 12 plug on the back of each one

the batteries test up fine as charged , but if i test the unit by switching off the mains 240 volt supply , they wont kick in as a UPS for some reason , i assume the RJ 12 plug has to be connected as a jumper in some way , or is there another device which connects to the RJ 12 to act as a controller ?

anyone know the RJ 12 jumper connections to make standby power kick in when the mains power is turned off ?

or suggest a link where i can find it ?

I cant find EMC listed on the DELL website , maybe they have discontinued their business relationship