Tag: HP EVA

SPC-1/E IOPS per watt – chart of the month

Posted on by Ray in IOPS, SPC-1, Storage energy use, Storage performance, Storage Performance Council
SPC*-1/E IOPs per Watt as of 27Aug2010
SPC*-1/E IOPs per Watt as of 27Aug2010

Not a lot of Storage Performance Council (SPC) benchmark submissions this past quarter just a new SPC-1/E from HP StorageWorks on their 6400 EVA with SSDs and a new SPC-1 run for Oracle Sun StorageTek 6780.  Recall that SPC-1/E executes all the same tests as SPC-1 but adds more testing with power monitoring equipment attached to measure power consumption at a number of performance levels.

With this chart we take another look at the storage energy consumption (see my previous discussion on SSD vs. drive energy use). As shown above we graph the IOPS/watt for three different performance environments: Nominal, Medium, and High as defined by SPC.  These are contrived storage usage workloads to measure the varibility in power consumed by a subsystem.  SPC defines the workloads as follows:

  • Nominal usage is 16 hours of idle time and 8 hours of moderate activity
  • Medium usage is 6 hours of idle time, 14 hours of moderate activity, and 4 hours of heavy activity
  • High usage is 0 hours of idle time, 6 hours of moderate activity and 18 hours of heavy activity

As for activity, SPC defines moderate activity at 50% of the subsystem’s maximum SPC-1 reported performance and heavy activity is at 80% of its maximum performance.

With that behind us, now on to the chart.  The HP 6400 EVA had 8-73GB SSD drives for storage while the two Xiotech submissions had 146GB/15Krpm and 600GB/15Krpm drives with no flash.  As expected the HP SSD subsystem delivered considerably more IOPS/watt at the high usage workload – ~2X the Xiotech with 600GB drives and ~2.3X the Xiotech with 146GB drives.  The multipliers were slightly less for moderate usage but still substantial nonetheless.

SSD nominal usage power consumption

However, the nominal usage bears some explanation.  Here both Xiotech subsystems beat out the HP EVA SSD subsystem at nominal usage with the 600GB drive Xiotech box supporting ~1.3X the IOPS/watt of the HP SSD system. How can this be?  SSD idle power consumption is the culprit.

The HP EVA SSD subsystem consumed ~463.1W at idle while the Xiotech 600GB only consumed ~23.5W and the Xiotech 146GM drive subsystem consumed ~23.4w.  I would guess that the drives and perhaps the Xiotech subsystem have considerable power savings algorithms that shed power when idle.  For whatever reason the SSDs and HP EVA don’t seem to have anything like this.  So nominal usage with 16Hrs of idle time penalizes the HP EVA SSD system resulting in the poors IOPS/watt for nominal usage shown above..

Rays reading: SSDs are not meant to be idled alot and disk drives, especially the ones that Xiotech are using have very sophisticated power management that maybe SSDs and/or HP should take a look at adopting.

The full SPC performance report will go up on SCI’s website next month in our dispatches directory.  However, if you are interested in receiving this sooner, just subscribe by email to our free newsletter and we will send you the current issue with download instructions for this and other reports.

As always, we welcome any suggestions on how to improve our analysis of SPC performance information so please comment here or drop us a line.

The price of quality

Posted on by Ray in Storage, Storage Quality, Strategy, System quality, Systems

At HPTechDay this week we had a tour of the EVA test lab, in the south building of HP’s Colorado Springs Facility. I was pretty impressed and I have seen more than my fair share of labs in my day.

Tony Green HP's EVA Lab Manager
Tony Green HP's EVA Lab Manager
The fact that they have 1200 servers and 500 EVA arrays was pretty impressive but they also happen to have about 20PB of storage over that 500 arrays. In my day a couple of dozen arrays and a 100 or so servers seemed to be enough to test a storage subsystem.

Nowadays it seems to have increased by an order of magnitude. Of course they have sold something like 70,000 EVAs over the years and some of these 500 arrays happen to be older subsystems used to validate problems and debug issues for current field population.

Another picture of the EVA lab with older EVAs
Another picture of the EVA lab with older EVAs

They had some old Compaq equipment there but I seem to have flubbed the picture of that equipment. This one will have to suffice. It seems to have both vertically and horizontally oriented drive shelves. I couldn’t tell you which EVAs these were but as they were earlier in the tour, I figured they were older equipment. It seemed as you got farther into the tour you moved closer to the current iterations of EVA. It seemed like an archive dig in reverse instead of having the most current layers/levels first they were last.

I asked Tony how many FC ports he had and he said it was probably easiest to count the switch ports and double them but something in the thousands seemed reasonable.

FC switch rack with just a small selection of switch equipment
FC switch rack with just a small selection of switch equipment

There were parts of the lab which were both off limits to cameras and to bloggers which was deep into the bowels of the lab. But we were talking about some of the remote replication support that EVA had and how they tested this over distance. Tony said they had to ship their reel of 100 miles of FC up north (probably for some other testing) but he said they have a surragate machine which can be programmed to create the proper FC delay to meet any required distances.

FC delay generator box
FC delay generator box

The blue box in the adjacent picture seemed to be this magic FC delay inducer box. Had interesting lights on it.

Nigel Poulton of Ruptured Monkeys and Devang Panchigar of StorageNerve Blog were also on the tour taking pictures&video. You can barely make out Devang in the picture next to Nigel. Calvin Zito from HP StorageWorks Blog was also on tour but not in any of my pictures.

Nigel and Devang (not pictured) taking videos on EVA lab tour
Nigel and Devang (not pictured) taking videos on EVA lab tour

Throughout our tour of the lab I can say I only saw one logic analyzer although I am sure there were plenty more in the off limits area.

Lonely logic analyzer in EVA lab
Lonely logic analyzer in EVA lab
During HPTechDay they hit on the topic of storage-server convergence and the use of commodity, X86 hardware for future storage systems. From the lack of logic analyzers I would have to concur with this analysis.

Nonetheless, I saw some hardware workstations although this was another lonely workstation sorrounded in a sea of EVAs.

Hardware workstation in the EVA lab, covered in parts and HW stuff
Hardware workstation in the EVA lab, covered in parts and HW stuff
Believe it or not I actually saw one stereo microscope but failed to take a picture of it. Yet another indicator of hardware descent and my inadequacies as a photographer.

One picture of an EVA obviously undergoing some error injection test with drives tagged as removed and being rebuilt or reborn as part of RAID testing.

Drives tagged for removal during EVA test
Drives tagged for removal during EVA test
In my day we would save particularly “squirrelly drives” from the field and use them to verify storage subsystem error handling. I would bet anything these tagged drives had specific error injection points used to validate EVA drive error handling.

I could go on and I have a couple of more decent lab pictures but you get the jist of the tour.

For some reason I enjoy lab tours. You can tell a lot about an organization by how their labs look, how they are manned, organized and set up. What HP’s EVA lab tells me is that they spare no expense to insure their product is literally bulletproof, bug proof, and works every time for their customer base. I must say I was pretty impressed.

At the end of HPTechDay event Greg Knieriemen of Storage Monkeys and Stephen Foskett of GestaltIT hosted an InfoSmack podcast to be broadcast next Sunday 10/4/2009. There we talked a little more on commodity hardware versus purpose built storage subsystem hardware, it was a brief, but interesting counterpoint to the discussions earlier in the week and the evidence from our portion of the lab tour.