Storage

Should We Panic About the KPTI/KAISER Intel CPU Design Flaw?

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As a followup to yesterday’s post, I’ve been asked: should we panic about the KPTI/KAISER/F*CKWIT Intel CPU design flaw? My answer was: it depends on a lot of unknowns. There are NDAs around a lot of the fixes so it’s hard to know the scope and effect. We also don’t know how much this will affect particular workloads. The folks over at Sophos have a nice writeup today about the actual problem (link below) but in short, the fix will reduce the effectiveness of the CPU’s speculative execution and on-die caches, forcing it to go out to main memory more. Main memory (what we call RAM) is 20x slower than the CPU’s L2 cache (look below for a good link showing …

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Intel CPU Design Flaw, Performance Degradation, Security Updates

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I was just taking a break and reading some tech news and I saw a wonderfully detailed post from El Reg (link below) about an Intel CPU design flaw and impending crisis-level security updates to fix it. As if that wasn’t bad enough, the fix for the problem is estimated to decrease performance by 5% to 30%, with older systems being the hardest hit. Welcome to 2018, folks. In short, an Intel CPU tries to keep itself busy by speculating about what it’s going to need to work on next. On Intel CPUs (but not AMD) this speculative execution doesn’t properly respect the security boundaries between the OS kernel and userspace applications, so you can trick an Intel processor into letting …

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Intel’s Memory Drive Implementation for Optane Guarantees its Doom

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A few weeks ago Intel started releasing their Optane product, a commercialization of the 3D Xpoint (Crosspoint) technology they’ve been talking about for a few years. Predictably, there has been a lot of commentary in all directions. Did you know it’s game changing, or that it’s a solution looking for a problem? It’s storage. It isn’t storage. It’s RAM. It isn’t RAM. It’s too slow to be RAM. It’s too small for storage. It’s useful now. Nobody will use it for years. Yup. Confusion. It’s because Optane is a bunch of different things. It’s consumer and enterprise, and it’s both storage and memory. There are plenty of articles out there on the technology itself. There’s a small M.2 version for desktops …

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Why Use SD Cards For VMware ESXi?

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I’ve had four interactions now regarding my post on replacing a failed SD card in one of my servers. They’ve ranged from inquisitive: @plankers why would you use an SD card in a server. I’m not a sys admin, but just curious. — Allan Çelik (@Allan_Celik) January 22, 2015 to downright rude: “SD cards are NOT reliable and you are putting youre [sic^2] infrastructure at risk. Id [sic] think a person like you would know to use autodeploy.” Aside from that fellow’s malfunctioning apostrophe, he has a good, if blunt, point. SD cards aren’t all that reliable, and there are other technologies to get a hypervisor like ESXi on a host. So why use SD cards? 1. Cost. Looking at …

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Table Stakes for Storage Arrays

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I was just looking at Andreas Lesslhumer’s post about blog posting volume in the virtualization community, and it’s depressing. I didn’t blog a whole lot here last year. Why was that? Because I was writing elsewhere! Speaking of that, the first half of my “Six Features You Absolutely Need on Your Storage in 2015” list is up over at The Virtualization Practice, wherein I outline what the table stakes are for enterprise storage arrays, get only slightly snarky about why we’re still discussing, as an industry, why & how to use flash, and highlight the good work some vendors are doing (SolidFire, Dell, and Tintri in this post, more in next week’s second part). Check it out.

Coho Data

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Over the last year or so I’ve been fortunate to work with a bunch of great folks over at Coho Data, who are coming out of stealth mode with the debut of their storage product, the DataStream[0]. I’ve got a write-up over at The Virtualization Practice on the device, but I’ve also got a prerelease unit running in my lab, and I’ve been liking it a lot. Neither Coho nor EMC nor Nutanix will like this comment, but if an Isilon got frisky with a Nutanix cluster the DataStream might well be the love child. Scale-out architecture and great software smarts on value commodity hardware. For both personal and technical reasons I’ve always liked the Isilon products, and they’ve done …

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VMware & Virsto

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Howard Marks has a great piece on VMware buying Virsto over at Network Computing (link is below): Some of my fellow analysts have lumped Virsto into the flash acceleration category along with caching solutions like Proximal Data, Sandisk’s Flashsoft and Intel’s CAS. While Virsto can use flash to accelerate some storage I/O, it’s not primarily a flash acceleration product. In fact, Virsto is a log-based, clustered file system that uses a dedicated log device, which can be a shared SSD, to accelerate virtual machine I/O. I saw Virsto for the first time at VMworld 2012, and it looked interesting as something that tries to turn a lot of the random I/O from a virtualization environment back into sequential I/O that arrays can better handle, while adding a …

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Backing Myself Up Using CrashPlan, TrueCrypt, and Hamachi

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For a long while now I’ve been looking for a decent & automatic way to protect the data on the multitude of computers I support in my personal life. I’ve been using a hodgepodge of external disks and synchronization software to keep a spare copy of my data, photos, and media, but with the impending birth of my daughter I figure I’m not going to have time or the willingness to mess around with kludgy solutions anymore. I also don’t want to run the risk of data loss when it comes to things my relatives would judge me on. “What do you mean you don’t have the video of her <doing some activity>?” I stumbled upon CrashPlan a few weeks …

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Why Is It Called "Resilvering?"

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Q: Why do some people refer to the process of remirroring or rebuilding a RAID 1 drive set as “resilvering?” A: Antique mirrors (the reflective kind you hang on a wall, or are in your bathroom) used silver (Ag) for the reflective coating, below the glass. Over time that silver would get tarnished and/or damaged, so you’d restore them by re-silvering them. I’m sure you’ve all seen this, where an old mirror has streaks in it but they’re below the glass. When your RAID 1 mirror set gets “tarnished” you resilver it and it’s shiny & new again. You can rebuild a RAID 5 array but you resilver a mirror. 🙂

If You Ever Needed Convincing About VAAI…

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If you needed any convincing about the benefits of VAAI, here’s a graph of what happened when I took our new VAAI-capable HDS AMS 2500, copied a 25 GB template VM to it, then cloned three more VMs from that template. I did the cloning one at a time, rather than in parallel, mainly because I was in shock that it took about 30 seconds for each one to complete and in my giddiness I didn’t think to do any other testing. I have only the Hitachi write rate highlighted, but that tells the story: So far, the only drawback I can see to the new VAAI offloads are just that you’ll need to rely more heavily on your array’s …

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