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Thread: SSD vs HDD?

  1. #51
    Untangle Ninja sky-knight's Avatar
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    Another SSD goes up in flames, this time to a customer that bought in January, first drive failed in February, now the replacement drive just died again.

    That's 2 32gb SSD drives from two different manufacturers (Kingston, and Transcend) that have failed in a single device within year 1.

    Use SSD at your own risk, I think Nexgen Appliances may just pull them entirely. I'm tired of the warranties, and I'm tired of the hurt customers.
    Rob Sandling, BS:SWE, MCP
    NexgenAppliances.com
    Phone: 866-794-8879 x201
    Email: support@nexgenappliances.com

  2. #52
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    In another thread I wrote of my research on the topic which suggests 32G is just too small and the drive will wear out quickly. I know you mentioned controller failures however the way SSD work is that for drives that are written to frequently, they need a fair amount of space to distribute the writes.

    32G for an untangle box isn't going to offer enough headroom especially for a busy network.

    http://www.anandtech.com/show/5518/a...-of-intel-ssds

  3. #53
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    Quote Originally Posted by DuckieHo View Post
    Any idea of the writes daily?

    Are they using SLC, eMLC, or MLC? Are they noticing the available space decreasing with wear?
    I can't say exactly. However lets just say these devices are on a very big corporate network running many gigabytes of traffic through a month. The drive arrays are not individually proactively monitored but the device will throw up a disk alarm when its time for a new one.

    http://www.infostor.com/index/articl...adds_ssds.html

    http://www.riverbed.com/us/company/n...ess_020910.php

    The Steelhead 7050 is the first WAN optimization appliance where the persistent data store is 100% resident on SSDs, minimizing disk access times and latency to allow it to deliver the speed necessary to handle extreme work loads. The Steelhead 7050 optimizes up to 100,000 concurrent optimized TCP connections and up to one Gigabit per second WAN-side throughput, and utilizes up to four 10 Gigabit Ethernet (10GbE) network interface cards.

    The Steelhead 7050-L 2.24 TB of raw SSD capacity (14 drives at 160 GB) and another two 300 GB hard disks (for data logging).

    I knew they had mechanical drives as well but now I know why. Thats where the bulk of writes takes place The SSD's are used for caching so less writes. There's a clue right there.

    Also this:

    The SSDs employ a RAID-like striping technique called FTS (short for fault tolerant storage) so the scratchpad data used by the optimization algorithms is protected as it is being chewed upon.

    I doubt untangle has anything this sophisticated in place to prolong the life of any SSD installed, but if a large enough drive is used it should not matter anyway.

    On my untangle box 52.77G is free representing 93% of the drive. My network has a low traffic volume so I should be fine for a long long time with this configuration.
    Last edited by keith_h; 10-20-2012 at 07:36 PM.

  4. #54
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    Default Starting Partition Alignment

    Unless Untangle installation starts to pay attention to starting partition alignment, anyone with an SSD is going to be kidding themselves. A misaligned partition causes serious issues on writes. You can Google for the details. Microsoft recognized this a long time ago with Vista. It automatically aligns its boot/system partition on a page boundary (basically 1024^2 = 1048576 bytes into the disk, you can verify this with System Information) on all disks. Of course, Windows 7 and 8 take care of this automatically under all installation options. It doesn't matter so much with a mechanical disk, but is extremely important with SSDs.

    Look. Here's what the default installation does (this is on a HDD, but it's the same for SSD)
    Code:
       Device Boot      Start         End      Blocks   Id  System
    /dev/sda1   *           1        8740    70204018+  83  Linux
    /dev/sda2            8741        9729     7944142+   5  Extended
    /dev/sda5            8741        9729     7944111   82  Linux swap / Solaris
    You want to kill an SSD? Do that ^^^^.

    Those small reporting, logging, and journaling writes are murder under these conditions. No wonder you guys are complaining about "mysterious" SSD failures/burnout/etc.

    If you care to, you can adjust the starting offset with Parted Magic after setup is complete.

  5. #55
    Untangle Ninja mrunkel's Avatar
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    Quote Originally Posted by GeneralEclectic View Post
    Unless Untangle installation starts to pay attention to starting partition alignment, anyone with an SSD is going to be kidding themselves. A misaligned partition causes serious issues on writes. You can Google for the details. Microsoft recognized this a long time ago with Vista. It automatically aligns its boot/system partition on a page boundary (basically 1024^2 = 1048576 bytes into the disk, you can verify this with System Information) on all disks. Of course, Windows 7 and 8 take care of this automatically under all installation options. It doesn't matter so much with a mechanical disk, but is extremely important with SSDs.

    Look. Here's what the default installation does (this is on a HDD, but it's the same for SSD)
    Code:
       Device Boot      Start         End      Blocks   Id  System
    /dev/sda1   *           1        8740    70204018+  83  Linux
    /dev/sda2            8741        9729     7944142+   5  Extended
    /dev/sda5            8741        9729     7944111   82  Linux swap / Solaris
    You want to kill an SSD? Do that ^^^^.

    Those small reporting, logging, and journaling writes are murder under these conditions. No wonder you guys are complaining about "mysterious" SSD failures/burnout/etc.

    If you care to, you can adjust the starting offset with Parted Magic after setup is complete.
    I'm sorry, but this is just wrong.

    There is so much abstraction between the partition table and the memory chips in an SSD that this just doesn't make any sense at all.

    Feel free to worry about this if you'd like, but it's like worrying about the path your spark plugs are taking in your car in order to get better gas mileage.
    m.


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    It often helps troubleshooting if you have a good network map. Look here if you want my advice on how to draw one.
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  6. #56
    Untangle Ninja sky-knight's Avatar
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    The fact that people are resorting to this level of black magic is simply underscoring the reality that SSD technology isn't ready for general consumption.

    I will point out once again, that ALL of my original assumptions of the technology have been proven false. And the only thing I've found "wrong" with SSDs over the last year have been manufacturing defects. These are a small percentage of drives, and they tend to be concentrated around production runs of similar devices. This is normal electronics manufacturing crap. It's just that for some odd reason, SSDs blow up 6-8 months in, and not within 30 days like other things. This reality alone is enough for me to move away from them, because a device blowing up 6 months in just ruins the customer's experience.

    They are getting better, and I suspect within the next year or two the entire conversation will be moot as the devices, and related firmware will be mature enough to operate just like normal drives. Except we'll have tools to predict NAND failure, warning systems built into the OS to deal with this, and can then take easy advantage of the extra performance.
    Rob Sandling, BS:SWE, MCP
    NexgenAppliances.com
    Phone: 866-794-8879 x201
    Email: support@nexgenappliances.com

  7. #57
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    "I'm sorry, but this is just wrong."

    So EVERY SSD manufacturer, and Microsoft are wrong? Ooooooo-K. There is so much documentation on this subject from responsible, reliable, and authoritative sources that anyone using an SSD can make up their own mind. I have no intention of arguing about it. Horse-Water-Drink. Go ahead, toast your SSDs, doesn't matter one bit to me.

  8. #58
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    Default Point, Set, Match.

    I wasn't going to bother with replying to you two any further, but since a lot of people may read this, it's not fair to others in the community to let your misinformation go unchallenged. To put a fine point on it, you two are WRONG. Not just a little bit, but major league. Fact is that no one, and I mean NO ONE in the SSD business, or the Windows or Linux O/S business agrees with you. You simply don't know what you're talking about, and I'm going to let Microsoft and the SSD manufacturers prove it.

    But first, consider this. I have visibility of just over 200 PC workstations and laptops, all of which run Windows 7 on SSDs. Like one of you, I have a small pile of SSDs on my bench. Only one difference -- these are all brand new spares. So, out of this population, I'm aware of 0 SSD failures because this pile doesn't seem to be shrinking. Now I wonder why that is. You are having poor results, while GE has pretty good results. Hmmmm. Maybe it's because Windows 7 (except for Enterprise) sets up with very close to optimized behavior when it detects an SSD. Maybe it's because original setups and image installs are partitioned on an SSD page boundary with a proper offset of 1048576 Bytes. Ya think? I can tell you guys that all these Windows installations are set for absolute minimum SSD writes. And there are simply no failures.

    Want to try a little experiment? Connect an HDD to a Win 7 box. Remove any existing partitions, and create a new one for the full disk. Format it. Now start up your favorite disk information utility (actually, System Information --> Components/Storage/Disks is the most convenient) and you tell me -- what is the partition starting offset? Okay, to save some time, I'll tell you. On most HDDs, it's 63 * 512Bytes = ~32KBytes. Now let's repeat using any old SSD. Remove any existing partitions and create a new one for the full disk. Format it. Now you tell me, what's the starting partition offset? Hint: it will be 1024 * 1024 = 1048576 Bytes. Hey!! Wait a minute! That's not the same as we got with the HDD. Hmmm Gee. I wonder why that might be. Think Microsoft knows something that you guys don't? Here's another hint: starting with Vista, MS has used a default starting partition offset of (drum roll, please)1048576 Bytes for SSDs. That includes original installation and any other routine disk partitioning/formatting operations.

    Now recall all the issues when people started using SSDs with XP? One of the many issues was starting partition offset. All the manufacturers recognized the problem and their support forums are FULL of discussion (which are typically supported by the manufacturers' employees) as to how to correct the problem.

    So here's Clue #1, you two: http://downloadcenter.intel.com/Deta...tion+alignment Do you see what's on that page at Intel? It's 1) a tool from Acronis, commissioned by and paid for by Intel, the purpose of which is what? And second on the list is a PDF that explains exactly what's going on and why the tool is necessary. Suggest you read it.

    Okay, still not convinced? How about Samsung. Here. Read this PDF: http://www.usenix.org/event/lsf08/tech/shin_SSD.pdf That's a Samsung engineer explaining, among other things, why starting partition offset is important (pages 5, 18) with a specific Linux orientation.

    What about everyone else? (No, I didn't search everywhere, but looked in some of the more likely places)

    Ubuntu 10 and later now installs the first partition at 1048576. Are they wrongheaded fools too who don't know what they're doing?

    Microsoft, Windows 7 Engineering - "Since SSDs tend to perform at their best when the operating systemís partitions are created with the SSDís alignment needs in mind, all of the partition-creating tools in Windows 7 place newly created partitions with the appropriate alignment." That's here: http://blogs.msdn.com/b/e7/archive/2...rives-and.aspx

    Crucial - " Performance can vary depending on hardware configurations, software, and more. These simple steps will ensure your SSD is configured correctly: ..... 5. Ensure the partition on the drive is aligned correctly. If you cloned your drive, we suggest a fresh install of the operating system. ...." That's here: http://forum.crucial.com/t5/Solid-St...ted/ta-p/65219 Posted by a Crucial employee who moderates the forum, so it's likely that he's not just blowin' smoke.

    Sandisk - right out of their KB: http://kb.sandisk.com/app/answers/de...on%20alignment Read #3, #4 and the note in blue. There's NO ambiguity there.

    Here's a Plextor employee saying the same thing in their forum: http://www.plextoramericas.com/index...&catid=27#5336

    Corsair, OCZ, etc. Same thing.

    Face it. You guys are just outvoted.

    Now here's a freebie for you. Just for gits and shiggles, I took a slightly used Corsair Force120 SATAII drive that didn't have a home and installed Untangle 9.0 (IIRC) on it. When it went into service, it had about 300GB of writes and 100% Media Wear. Now this is a minimalist, very lightly loaded system. Default reports. Ad blocker, Anti-Intrusion, Virus Lite, Spyware modules. That's it. At most, about 1.8 GB was stored on the disk at any one time. Took it out after four or five (I don't recall exactly) months and was pretty shocked at what I found. 2.2TB writes and (here's the weird part) Wear Indicator 62%. Holy Cow. The obvious conclusion here is that currently Untangle is simply an unsuitable environment for SSDs (sound familiar to those who have a pile of failed drives?). Why is that? 1) Partition alignment is wrong and causes excess erasures and re-writes. 2) Untangle is *constantly* (once every one or two seconds) writing SOMETHING (I was never able to discover what, and a single byte is all that's necessary to cause the problem) to the drive causing those excessive erase-rewrite cycles thus wearing out the drive. I can tell you that I have never seen any wear pattern anything like this in a Windows box. Not even close. I've looked at a bunch of SSDs that have 10K+ hours on them and 1-2TB writes that are still sitting at 95%-100% wear levels.

    So if I were in the Untangle business, which fortunately I am not, I'd be following DASHPUPPY's advice above (actually I think he's right on ALL counts) and install a nice WD Scorpio Black WD1600BEKT and call it a day. You get fairly low power, reasonable speed, enough capacity, little noise, and no weird SSD problems.

    Finally, I'm done with this thread. I don't need the arrogant "I'm always right" know-it-all replies, and do not feel it's worth more of my time to refute your baseless misinformation any further. The references above speak for themselves.

    Have a nice day.
    hescominsoon, wallzone and joshgay like this.

  9. #59
    Untangle Junkie dmorris's Avatar
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    I have not really read the entirety of this thread, but I thought I would chime in about our thoughts re: SSDs and Untangle.
    This thread was started in early 2012, so this is somewhat of a moving target.

    In 9.1 and 9.2 (when this thread was posted), reports was super disk I/O intensive and the performance benefit of an SSD was quite real.
    An SSD would tremendously improve disk performance would help the entire system run more smoothly.

    Of course, as some discovered, this performance came at some cost. Much of the benefit of Untangle comes from the fact that
    it records whats going on in your network which means its constantly writing "events" about whats happening to its database.
    This use case is not ideal for SSDs and some users reported reliability issues, especially with the cheaper brands.

    Much of this thread seems to explore if the "reliability" issue is real, and if an SSD makes sense on Untangle.

    With 9.3 and especially 9.3.1 all this has changed because of a few major changes in the software.
    In 9.3 and 9.3.1 contains a few massive changes that totally changes the disk I/O requirements of Untangle.

    Firstly, we moved away from hibernate to direct SQL and removed incremental reporting that ran every few minutes to churn events.
    The new mechanism requires much less work as events are written directly to their final destination and there is no incremental task that runs occasionally to churn events.
    Secondly, we moved settings out of the database and into files. This means that the database is *solely* used for events and can be tuned spefically for this use case.
    Change postgres tuning specifically for this use case gave us a 10-20x improvement in event write speed.

    We've been tracking reports/events performance of 9.3.x closely on large sites and while there is always more work to be done, the disk I/O requirements are massively less than previous versions.
    We're now seeing huge sites run on fairly slow disks without major issues.

    Ultimately, this means that the performance benefit of an SSD is far less important, and the increased reliability of a spinning-media hard drive makes sense in most cases.
    Given these changes, Untangle will be switching its own appliances to enterprise-class spinning-media hard drives, as it just makes more sense when you factor in the cost/performance/reliability of the two options.
    (My understanding is any current appliance owners having issues will have an option to switch, and of course is covered by warranty)

    Does this mean your current custom SSD-based Untangle is a ticking time bomb? Not really.
    Obviously there are a huge number of variables like which version of Untangle you are using (9.3.x vs 9.2.x and prior), what brand, and how many events your Untangle is writing.
    We've seen many brands performance just fine under pretty big loads, but we've also seen some cheap brands have problems.

    If you're choosing SSD vs HDD in a new server, I'd suggest HDD as it makes more sense given the new requirements.

    Thanks for all that have contributed to this thread and keeping us up to date on SSD performance in the field, and for providing colorful and passionate entertainment.
    GeneralEclectic, sky-knight, dashpuppy, keith_h, untangleme, Mathiau, DuckieHo, etc.
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  10. #60
    Untangle Ninja sky-knight's Avatar
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    Thanks Dirk, I'm curious to see what the next year will bring. Because, you're dead on as usual, this is a huge moving target. There is no magic fix. We'll have a new OS soon that will help this process even further, as Squeeze will bring in TRIM.
    Rob Sandling, BS:SWE, MCP
    NexgenAppliances.com
    Phone: 866-794-8879 x201
    Email: support@nexgenappliances.com

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