topic Re: EVA 8400 Processor Speed in HPE EVA Storage

EVA 8400 Processor Speed

BrianPB — Tue, 19 May 2009 15:53:40 GMT

Anyone know the Processor Speed of the 8400's controllers? Have they gone to 64bit? Or is it still 32bit?

Re: EVA 8400 Processor Speed

Steven Clementi — Tue, 19 May 2009 16:26:57 GMT

Why would this even matter? (Just wondering)

Re: EVA 8400 Processor Speed

Víctor Cespón — Tue, 19 May 2009 18:08:12 GMT

I don't think that has been published anywhere public, but anyway it's irrelevant, the controller CPU has never been limiting the performance on an EVA.

Moving to 4 or 8 GB of cache per controller, and to SSD drives gives a much bigger performance improvement.

Re: EVA 8400 Processor Speed

BrianPB — Tue, 19 May 2009 18:35:09 GMT

Not thinking about performance per se, but it seems like scalability is lacking slightly in the 8400. Was hoping for something more. Wondering if processor speed limits the amount of drives the back end can handle.

Re: EVA 8400 Processor Speed

Víctor Cespón — Tue, 19 May 2009 19:03:26 GMT

Can't follow your logic. The CPU on an EVA8000, even fully loaded with 18 enclosures seldom goes above 20%.

The 8400 has 20% more performance, 3 independent loop pairs with 9 enclosures, 108 drives per loop.

The limit for I/O are always the disk drives. Assumming a typical 8K I/O size, and a maximum 150 I/Os per drive (15K drives), that's 1.2 MB/s per drive or 130 MB/s per loop. The backend is all 4 Gb/s, so...

Re: EVA 8400 Processor Speed

BrianPB — Tue, 19 May 2009 19:36:23 GMT

Right. I guess I'm wondering why they limit the 8400 to 324 Drives. I can understand it with the 8000/8100 with the CAN switches, but you would think now that they have gone to the cascading disk shelves that they would have offered more capacity especially in the 8400. Thought it might have been processor limited, or perhaps just marketing... :)

Re: EVA 8400 Processor Speed

Víctor Cespón — Tue, 19 May 2009 20:54:49 GMT

No, that's due to the FC_AL protocol. There are 127 AL_PAs per loop, you need 108 for the drives, 9 for the I/O modules and 2 for the controllers.

Not enough addresses to have 10 enclosures per loop. Anyway, the I/Os are daisy-chained, a packet has to pass through several I/Os to reach it's destination disk. Not good to have too many.

Re: EVA 8400 Processor Speed

Susan Tafolla — Tue, 01 Sep 2009 16:35:13 GMT

what if the IO is 256K rather than 8K? the max IO per disk could be 256K x 150 ios/second?

Re: EVA 8400 Processor Speed

Patrick Terlisten — Tue, 01 Sep 2009 17:29:08 GMT

Hello,

there is a german saying: "Haette, waere, wenn". You need 108 drives, with each drive delivering 150 IOPS with 256k IOs to fill up a 4 GB backend-loop. Sure you can do this, but that's theory.

Think about EMCÂ² CLARiiONs which are still using Intel P4 CPUs on their storage processor.

The limiting factor are the loops, not the controller. The cache upgrade is more marketing then true need. HP no differs anymore the cache in differnt parts, cache is cache.

Best regards,
Patrick

Re: EVA 8400 Processor Speed

Kranti Mahmud — Wed, 02 Sep 2009 03:50:45 GMT

Hi BrianPB,

Check this PDF: http://hp.sharedvue.net/sharedvue/resources/tsg-fg-storageworks_array.pdf

Rgds-Kranti

Re: EVA 8400 Processor Speed

Uwe Zessin — Wed, 02 Sep 2009 05:07:44 GMT

Patrick,
a single "4 GB backend-loop" has a bandwidth of 400 MegaBytes per second, not 4,000.

Re: EVA 8400 Processor Speed

Patrick Terlisten — Wed, 02 Sep 2009 05:51:14 GMT

Hello Uwe,

you're right, my fault. Maybe I should repeat some classes in primary school to refresh my knowledge in elementary mathematics. :-|

Best regards,
Patrick

Re: EVA 8400 Processor Speed

Torsten. — Wed, 02 Sep 2009 08:41:42 GMT

I found a source that talks about the processor:

http://de.wikipedia.org/wiki/Enterprise_Virtual_Array

Sorry, I did not found something in english wiki.

It says, PowerPC CPUs are used, but I don't think this is relevant for overall array performance in any way.
BTW, some of them have even 128bit processing in certain units, AFAIK.

Re: EVA 8400 Processor Speed

Patrick Terlisten — Wed, 02 Sep 2009 10:10:10 GMT

Hello Torsten,

I wrote the first version this wiki article nearly a year ago. I don't know if the PPC cpu is doing all the work, rather I think that the PPC is supported by some other special ASIC. There is another hint in the OCP menu under "System Information -> PIC -> PowerPC Processor".

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c00365593

Best regards,
Patrick

Re: EVA 8400 Processor Speed

Torsten. — Wed, 02 Sep 2009 10:23:45 GMT

Nice work.
I know for sure it is a PPC CPU :-) but it doesn't really matter.

Re: EVA 8400 Processor Speed

Uwe Zessin — Wed, 02 Sep 2009 10:40:25 GMT

> some other

There are a number of special ASICs to do the work.

Re: EVA 8400 Processor Speed

Jeffrey Wolfanger — Tue, 06 Jul 2010 11:47:20 GMT

Well the CPU on 8400s do often go above 20% in production I see them as high as 90 with a mean at 70% and that is far from fully loaded. So to the comments on to why it matters and 8400 isnt an 8000 and it does matter.

Re: EVA 8400 Processor Speed

DavidWarburton — Fri, 13 Aug 2010 10:38:45 GMT

I'm having the same problem with our 8400 too.

We had some really weird issues where one controller would be happily hovering around the 30% CPU usage but the other would either be at 0% or shoot up to 90%+ (either quick spikes or sustained for about 10-20 seconds).

I moved a really heavily used LUN to the other controller and both controllers are now much more evenly matched - sadly both controllers are now steady between 70-90% !!!

All these LUNs were previously on an 8100 and although I don't have any stats to back up my thoughts, we didn't seem to be suffering from such bad performance!

Can anyone give me any tips as to what's causing such high CPU usage? I mean I can see what LUNs have high IO and high latency, but I wouldn't have thought that CPU usage should EVER get this high (at least not sustained).