Hardware has set the pace for latency, time for software to catch up

I can’t recall the last storage system installation that didn’t have some amount of solid state drives in its configuration. And for good reason: we’re rapidly getting used to the performance benefits of SSD technology. Faster applications usually result in real business value. The doctor treating patients can get his paperwork done faster and thus has time for more patients in a day. Or the batch job processing customer mailing lists or CGI renderings completes sooner, giving you a faster time to market.

To reduce the application wait times even further, solid state drives need to be able to achieve even lower latencies. Just reducing the media latency won’t cut it anymore: the software component in the chain needs to catch up. Intel is doing just that with Storage Performance Development Kit (SPDK).

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Squashing assumptions with Data Science

Nimble Storage InfoSightEarlier this year Nimble Storage announced their all-flash array called the Predictive Flash Platform; you can read my thoughts on the launch over here. InfoSight is one of the core components of that announcement, which is why we had the opportunity for a fireside chat with the Nimble Storage data science team. We discussed the workings of InfoSight & VMVision and how this relates to actual benefits for an owner of a Nimble Storage array. This post will also touch on some of the key points discussed during the later Storage Field Day 10.

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VMAX Performance – Queue Depth Utilization Explained

Queue Utilization AlertRecently I’ve ran a project for a new EMC Symmetrix VMAX 10k installation. The install was a breeze and the migration of data to the system fairly straightforward. The customer saw some good performance improvements on the storage front and there is plenty of capacity in the system to cater for immediate growth. Yet when I opened the Unisphere for VMAX interface and browsed to the performance tab, my heart skipped a beat. What are those red queue depth utilization bars? We were seeing good response times, weren’t we? Were we at risk? How about scalability? Lets dig deeper and find out.

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Unisphere for VMAX – Alerting & Performance

Unisphere for VMAX dashboardSeveral weeks ago we performed a resiliency test on a VMAX10k that was about to be put into production. The customer wanted confirmation that the array was wired up properly and would respond correctly in case there were any issues like a power or disk failure.  This is fairly standard testing and makes sense: better to pull a power plug and see the array go down while there is no production running against it, right?

We pulled one power feed from each system bay and storage bay. Obviously: no problem for the VMAX, it dialed out, notified EMC it lost power on a couple of feeds and that’s it. Next up we yanked out a drive: I/O continued, the array dialed out to EMC that something was wrong with a drive, but… we didn’t see anything in Unisphere for VMAX!

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FAST VP: Let it do its job!

FAST VP in actionNot all data is accessed equally. Some data is more popular than other data that may only be accessed infrequently. With the introduction of FAST VP in the CX4 & VNX series it is possible to create a single storage pool that has multiple different types of drives. The system chops your LUNs into slices and each slice is assigned a temperature based on the activity of that slice. Heavy accessed slices are hot, infrequently accessed slices are cold. FAST VP then moves the hottest slices to the fastest tier. Once that tier is full the remaining hot slices go to the second fastest tier, etc… This does absolute wonders to your TCO: your cold data is now stored on cheap NL-SAS disks instead of expensive SSDs and your end-users won’t know a thing. There’s one scenario which will get you in trouble though and that’s infrequent, heavy use of formerly cold data…

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VNX2 MCx FAST Cache improvements

EMC World 2013 - Day 3 306MCx FAST Cache is an addition to the regular DRAM cache in a VNX. DRAM cache is very fast but also (relatively) expensive so an array will have a limited amount of it. Spinning disks are large in capacity and relatively cheap but slow. To bridge the performance gap there are the solid-state drives; both performance wise and cost wise somewhere between DRAM and spinning disks. There’s one problem though: a LUN usually isn’t 100% active all of the time. This means that placing a LUN on SSDs might not drive your SSDs hard enough to get the most from your investment. If only there was software that makes sure only the hottest data is placed on those SSDs and that will quickly adjust this data placement depending on the changing workload, you’d have a lot more bang for your buck. Enter MCx FAST Cache: now with an improved software stack with less overhead which results in better write performance.

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VNX2 MCx Cache improvements

MCx Cache improvements Forced FlushingWhen troubleshooting performance in a CLARiiON or VNX storage array you’ll often see graphs that resemble something like this: write cache maxing out to 100% on one or even two storage processors. Once this occurs the array starts a process called forced flushing to flush writes to disk and create new space in the cache for incoming writes. This absolutely wrecks the performance of all applications using the array. With the MCx cache improvements made in the VNX2 series there should be a lot less forced flushes and a much improved performance.

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EMC Elect Redefining Possible at MegaLaunch IV

(C) Sean Thulin“Check your email ;)”. That was the first Twitter DM I read one sleepy morning in June. It’ll suffice to say, a minute later I was wide awake: I was chosen to represent the EMC Elect at the EMC “Redefine Possible” MegaLaunch event in London (UK)! I knew about these launch events because my colleague Rob attended one last year in Milan. Excitement started building and a couple of hours later I figured out I wasn’t going alone…

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VNX2 hands-on (a.k.a. Who stole my SPS?!)

A VNX5400 installed in the rackIn September 2013 EMC announced the new generation VNX with MCx technology (or VNX2). The main advantage of the new generation is a massive performance increase: with MCx technology the VNX2 can effectively use all the CPU cores available in the storage processors. Apart from a vast performance increase there’s also a boatload of new features: deduplication, active-active LUNs, smaller (256MB) chunks for FAST VP, persistent hotspares, etc. Read more about that in my previous post.

It took a while before I could get my hands on an actual VNX2 in the field. So when we needed two new VNX2 systems for a project, guess which resources I claimed to install them. Me, myself and I! Only to have a small heart attack upon unboxing the first VNX5400: someone stole my standby power supplies (SPS)!

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EMC World 2014 – Redefine your storage

EMC World 2014 Las Vegas StripEMC World 2014 is back in town, this time with the REDEFINE punchline. After some logistic challenges to get here the show is on the road; general sessions, break-out sessions, hands on labs (HOL). So what’s up with the REDEFINE punchline? What are we redefining in the IT / data infrastructure? And what are the EMC Elect doing at EMC World when not flooding your Twitter feed?

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