Defragmenting SSDs

By Poppa Bear
Jul 13, 2012
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  1. The consensus of opinion seems to be that you should not defrag SSD hard drives, not so much because it's harmful but because of the different NAND filing system used by SSDs. However, there is still quite a lot of controversy in various forums on this topic. Some say defragging harms it because it unnecessarily reduces the life span.

    Because SSDs have a finite number of writes, they spread the data evenly and randomly over the whole recording surface to maintain even wear. However, data which is corrupt or no longer serves any useful purpose is not written over, as the SSD can't detect that it is useless. And this tends to defeat the purpose of even wear.

    Windows 7 TRIM is meant to pro-actively delete corrupt or obsolete data on the SSD, and is set to run by default. However, it only works on single disk installations, and even though running in Windows, is not necessarily being implemented on the hard drive. For TRIM to function the operating system, storage drivers and solid-state drive must all support the TRIM command.

    This is a link HERE to a PDF article on optimizing SSD storage,and which says among other things:

    "The principle issue is write speed degradation due to free space fragmentation... "

    When I bought my first Corsair Force SATA3 SSD a year ago, the computer store told me to use it just like a normal HD. So I had been defragging it for almost a year when I became aware that you shouldn't defrag them.

    I contacted Corsair Tech Support to query whether I would have done any damage, and this was there reply:

    "The SSDs we develop will last up to 20 years even if you write more than 20GB of information a day (which is well beyond the normal user). I believe you will replace your system long before you replace the SSD."

    Does anyone know of any 3rd party software that acts independently and safely, to keep an SSD at optimum performance?

    Update: The link above for some unknown reason did not work. Have replaced it with correct address.
  2. jobeard

    jobeard TS Ambassador Posts: 13,040   +223

    Hmm; Guess I'm the cynic - - I don't buy the association of write speed -> fragmentation.

    The advantage of the SSD is it voids the SEEK and ROTATIONAL delay of the HDD and the
    only component left for the I/o operation is the TRANSFER time. That said, understanding that
    a defrag addresses the SEEK time and the SSD has none, defrag on the SSD is meaningless.

    Read/Write to bock X vs. block Y is no different than accessing Page X vs Y in memory (consider real and not vm systems).
  3. Poppa Bear

    Poppa Bear TechSpot Enthusiast Topic Starter Posts: 266

    What you say makes sense. I don't know enough about it to dispute or agree with what I read, and the graphs shown by HyperFast via the link in my opening post made me a bit worried.

    I've also been discussing SSDs generally with Corsair tech support and this was there latest feed back to me:

    1.) The defrag does not damage the drive but will put onto the drive a very large number of writes and re-writes so your drive will start to slow down faster than those drives you do not defrag.

    2.) You can keep the Acronis image of Win7 as long as you remember to disable the Defragmentation service through Administrative Tools -> Service. But for optimal performance, a clean install is always the best thing to do.

    Their first point tends to suggest that the hard drive will eventually slow down anyway, whether you defrag or not?

    Their second point was in regard to an Acronis image I had made of my OS after a fresh installation, but where I had defragged the system before creating the Acronis image. I think I'll do a clean install and new image without the defrag.

    Before doing the new installation, would an unconditional format totally remove all data from the HD so as to get a totally clean start again?
  4. slh28

    slh28 TechSpot Paladin Posts: 1,925   +170

    Unless you're constantly writing huge amounts of data it's unlikely defragging will damage the SSD, by the time you notice any degradation in performance the drive will only be worth peanuts anyway given the direction of SSD prices lately. But defragging is unnecessary for SSDs, low access times are basically the main selling point of SSDs.
  5. Poppa Bear

    Poppa Bear TechSpot Enthusiast Topic Starter Posts: 266

    That makes sense. Since doing the last post I have come across two relevant articles.

    The first one HERE confirms that current vintage SSDs have extremely long life. It's a very long post, but also very thorough and pretty much says it all.

    The second HERE re Plextor Truspeed, confirms what Diskeeper had to say in the PDF mentioned in my opening post re optimizing performance. When opening this link, click on the April 2012 issue and see pages 54-56. Page 56 looks like the same thing Diskeeper does with Hyperfast. Once on the page right click it to zoom and can be moved around to read it.

    Corsair say in their FAQs that you do not have to tweak your OS to maintain performance of their SSDs. Add to that Windows TRIM, and the fact that most reputable brands of SSDs have "garbage collection" inbuilt ... and I don't think the average user would have much to worry about.

    I'm going to adopt a hands on attitude of using current SSD for a few months, (without defragging), to see if I get the loss of performance suggested in Diskeepers PDF. And if I do, I'll run HyperFast in the free trial version of Diskeeper to see if it makes a difference.
  6. Marnomancer

    Marnomancer TechSpot Booster Posts: 808   +51

    Don't normal HDDs still have a shorter life than SSDs?
  7. jobeard

    jobeard TS Ambassador Posts: 13,040   +223

    Debatable - - Since '87 and my first system (knock on wood) I have YET to lose an HDD.
    Early this spring, I did lose my Toshiba Laptop due to BIOS/mother board failure - - and that was a first too.
  8. LNCPapa

    LNCPapa TS Special Forces Posts: 4,201   +229

    I've lost maybe a dozen - but considering how many I go through that's not a very high percentage. I haven't lost an SSD yet but I only have 2 * SATA and 1 * mSATA.
  9. Marnomancer

    Marnomancer TechSpot Booster Posts: 808   +51

    Yes, my HDD never failed. So if SSDs are better, there is no reason for me to fret about lifespan.
  10. jobeard

    jobeard TS Ambassador Posts: 13,040   +223

    Consider the history of e-prom's; finite modifications! Apparently, the number of writes has an effect on the speed with which the next write takes to complete, thus measurable degregation in performance. This is quite different than the issue forcing defrag of an hdd, namely to locate a file into contiguous sectors to afford serial reading.
  11. Darth Shiv

    Darth Shiv TechSpot Evangelist Posts: 1,086   +154

    Basically what they are referring to there is the whole point of TRIM. Highly recommend to read the wiki. Essentially as more blocks have data written to them, the SSD knows data was written to them but it does not know when they are deleted as Windows only bothers deleting the FAT table entries. For the SSD to write new data to a block that has been previously partially used, it has to read/erase/rewrite the contents. Which is the performance degradation...

    So it basically the SSD not knowing what blocks the file allocation tables say are still in use which is the problem. TRIM just passes on the info "hey this block is not being used anymore" so the SSD can do some tidy-up and not lose performance.

    All you need is a TRIM supporting OS e.g. Win7 or later, a trim supporting motherboard SATA socket (e.g. Intel Core I series or later off the top of my head. Not sure about AMD.), TRIM supporting DRIVERS (this can be tricky to ascertain but onboard intel sata with intel RST drivers will handle this). It will then be automagic.

    RAID with TRIM to my knowledge is not supported by any motherboard chipset prior to IvyBridge. 3rd party solutions such as OCZ RevoDrive 3 also support TRIM on RAID (looking at wikipedia they claim you need Win8 for this) but last I checked you cannot plug 2 Vertex 4's for example into an i5-2500K desktop system and use RAID and have TRIM enabled.
    cliffordcooley likes this.


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