Creating a "hybrid drive" with a SSD and a HDD

Discussion in 'MacBook Pro' started by twocircles, Apr 24, 2015.

  1. twocircles, Apr 24, 2015
    Last edited: Apr 24, 2015

    twocircles macrumors newbie

    Sep 26, 2011
    My optical drive in my late 2011 MBP recently died, so I have been considering options. One of which is, of course, replacing the optical drive with an SSD. Then, other options present themselves, RAIDs and so on.

    Today, I was on eBay, I saw this in a listing. "Fusion Drive: A 100GB SSD (2 years old, OCZ Agility 3 AGT3-25SAT3-120G 2.5" 120GB SATA III MLC Internal SSD) combined with a brand new 1TB HD (Samsung/Seagate Spinpoint M8 ST1000LM024 1TB 5400 RPM 8MB Cache SATA 3.0Gb/s 2.5" HDD). They're connected as a Logical Volume Group exactly the way newer Macs are (Fusion Drive), which makes it much snappier than it originally was when it only had an HD. The HD has been placed in an enclosure where the original DVD drive was."

    It seems that with Yosemite, Logical Volume Group is now an option in Disk Utility setup. Can someone verify this?

    If you are willing to sacrifice your Optical Drive, I would think no one would ever again consider buying a hybrid drive for a Mac. Just add a relatively inexpensive, small (128-256 GB) SSD, and you're good to go.

    Previously, it had been suggested to me that if I was not going to set up a dual-SSD RAID, that my best performance increase would come by putting my OS and apps on the SSD and data and directories that get written to a lot on the HDD. I should set it up this way because I was told that the life of an SSD is dramatically shortened when it has to write a lot.

    What would the advantage of setting up a Logical Volume Group versus putting OS and apps on the SSD and data on the HDD? Is there a file management algorithm in the LVG that keeps most-read files on the SSD? Does it also move most-written files to the HDD? What else does it do?

    I had rejected getting a hybrid drive because it was my understanding that they really only speed things up during a reboot. This is why most owners don't see a big performance increase over a 7200 rpm HDD. Since I only reboot my MBP once every week or two, this is no big deal.

    I am interested in app access and daily operations. Unless an LVG helps speed up daily operations and extend hardware life, I would rather set up the drives the other way as separate volumes. I've seen machines set up like that and they fly.

    Does anyone have experience with both of these setups?
  2. twocircles thread starter macrumors newbie

    Sep 26, 2011
    Although I had searched old posts, I had not searched for "Logical Volume Group", which I just did. This linked thread expresses some opinions on some of the questions I have asked.

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