Difference between having one SPS vs. two SPS's?

Rip,
For context; the purpose of the SPS unit(s) is to provide power in the event of a site AC power outage so the Storage Processors can save the contents of Write Cache to persistent media (some of the disks in Bus 0 Enclosure 0). Note that in the absence of any fully charged SPS unit the Write Cache will not be enabled, and also note there is a weekly test of each SPS unit performed by the array. Having two SPS units a) allows the Write Cache to stay enabled through the weekly SPS testing, and b) provides an additional layer of protection in the unlikely event that one SPS unit fails during a site AC outage.

Regards,
DGM

the first sps to connect PSA and DAE-OS
the second SPS to connect PSB and DAE-OS
so two SPS to guarantee data integrity in case of power failure

That makes sense. So for purposes of data integrity, I would want to set all the LUNS owned by SPA in case of a power failure. And SPB would just be a standby in case of an SP failure, correct?

Thanks for the quick response.

Rip

Rip,
The Standby Power Supply batteries supply backup power to the Storage Processor Enclosure, not the individual Storage Processors. There are two to provide redundancy in the backup power to the Storage Processor Enclosure, not a particular Storage Processor.

You will want to balance the LUN ownership between SPA and SPB to balance the utilization of the Storage Processors. Each Storage Processor is active and services LUN access, but only one owns a LUN at a time.

Also, if you are up for a bit of reading I highly recommend the following whitepapers on Powerlink. Just perform a search using the title. These white papers will answer a lot of questions regarding the management and configurations of the arrays.

EMC CLARiiON Fibre Channel Storage System Fundamentals

EMC CLARiiON Best Practices for Fibre Channel Storage

CLARiiON High Availability (HA) Best Practices

so SPS is connected to PowerSupply A and PowerSupply B, not to SPA and SPB but ti guarantee data integrity we have to have redundant SPS

check this pic http://i37.tinypic.com/2py93ra.jpg

anyway thx arnah

Actually if you look at the diagram you referenced, each SPS connects to each Power Supply AND to each SP.

Power Comes into the array through two SPS, and then each SPS distributes power to one of the power connection for the SPE and DAE 0_0. There is also a data connection from each SPS to each SP. This allows the SPS to notify the SP that it needs to dump cache, and for the SP to monitor the status of the SPS.

Right, the Storage Process receive power from the Storage Processor Enclosure, not that Standby Power Supply. As Allen pointed out the connection between the SP and SPS is a data cable.

The job of the SPS is to provide power to the SPE and DAE0 on Bus 0 in the event of power loss. A power failure will cause the SPS to send a signal to the SP telling them to dump data in cache to the vault disks and power down.

Yep, you got it.

EMC publishes setup guides for each CLARiiON model on Powerlink. It will describe the physical connections for power and data cabling complete with diagrams. You should download the config guide for the array you are deploying for the complete details.

I am not sure but i think CX200/300 come with one SPS

advantage of having one SPS , less Cost , Disadvantage single point of failure incase of power loss and sps failure
Disadvantage of two sps , more cost
advantage of two sps , no SPF , guarantee data integrity and HA

SPE and DAE-OS Power Supply ¿A¿ to the SPS ¿A¿ on the right
SPE and DAE-OS Power Supply ¿B¿ to the SPS ¿B on the left
SPS ¿A¿ monitoring cable to SPA SPS Port on the right
SPS ¿B¿ monitoring cable to SPB SPS Port on the left
SPS ¿A¿ to the PDU on the right
SPS ¿B¿ to the PDU on the left
DAEs above the DAE-OS directly to the PDU



so SPS A is connected to PS A on SPE
and SPS B is connected to PS B on SPE
DAE-OS the Enclosure that contain vault drives

The storage arrays come with two SPS standard. I don't know if you can have it removed from the quote to cut costs. I don't know why you would want to either.

Our 300 definitely came with 2, but I'm not sure if there was an option to get the second one. We would never buy without the second even if the option existed.

That was the only one that I am aware of.