Lax25

Q: MacBook Pro Data Doubler One Volume

So I recently bought the data doubler kit from Other World Computing for my MacBook Pro. My biggest question I have is how I can effectively get my MacBook Pro to see these drives as one volume. I have attempted to make a stripe RAID and the concatenated RAD through disk utility in the recovery mode. The issue I run into is that when I go to install OS X it brings up a warning how I wont be able to use the disk repair or FileVault if I install OS X onto this volime since it is RAID. Now is there a way around this? I want to be able to use FileVault and disk utility on my drives.

 

i know I can create a symbolic link to one of the drives if I really wanted to but I thought it would be more convenient to just see both drives as one volume instead of two.

 

 

Let me know what your guys have done!

MacBook Pro (13-inch Early 2011), OS X Yosemite (10.10.4), Data Doubler by Other World Comp.

Posted on Jul 14, 2015 5:09 PM

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Q: MacBook Pro Data Doubler One Volume

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  • by Kappy,

    Kappy Kappy Jul 14, 2015 5:16 PM in response to Lax25
    Level 10 (271,057 points)
    Desktops
    Jul 14, 2015 5:16 PM in response to Lax25

    Those are restrictions of using a RAID as a startup volume, which in itself is a bad idea. Stay away from using a RAID. Exactly, why do you wish to accomplish? Do you have two HDDs installed or did you install an SSD to go with the HDD? If your optical drive slot is rated for 3 Gb/s then you really don't want to do anything that would effectively reduce the speed of the drive connected in the actual drive location which is a 6 Gb/s interface. Tying those two together will give you a 3 Gb/s effective interface for both drives. You may wish to think about an SSD in the original drive location and an HDD in the optical drive bay.

  • by Lax25,

    Lax25 Lax25 Jul 14, 2015 5:32 PM in response to Kappy
    Level 1 (0 points)
    Jul 14, 2015 5:32 PM in response to Kappy

    I want to do this because in my mind it's a pain in the butt to deal with two seperate drives intead of just my computer showing me one.

     

    Both drives are SSD 6Gb/s and both ports are 6Gb/s.

     

    All I want is for them to look like one drive so I don't have to think "hey this drive is filling up let's put this stuff over here." It makes more sense to have one volume which spans both SSDs and my computer deals with which drive it actually goes on, not me.

  • by Kappy,

    Kappy Kappy Jul 14, 2015 9:24 PM in response to Lax25
    Level 10 (271,057 points)
    Desktops
    Jul 14, 2015 9:24 PM in response to Lax25

    Then you first need to configure a striped RAID using Disk Utility. If you open Disk Utility then click on the Help menu and select Disk Utility Help, look for RAID in the search field. You should find instructions on how to setup the RAID.

     

    Now, you cannot install OS X on a RAID from scratch using the installer. Instead, you must install OS X on a single drive, then clone that system to your RAID. You can then boot from the RAID.

     

    RAID Basics

     

    For basic definitions and discussion of what a RAID is and the different types of RAIDs see RAIDs.  Additional discussions plus advantages and disadvantages of RAIDs and different RAID arrays see:

     

    RAID Tutorial;

    RAID Array and Server:

    Hardware and Service Comparison.

     

    Hardware or Software RAID?

     

    RAID Hardware Vs RAID Software - What is your best option?

     

    RAID is a method of combining multiple disk drives into a single entity in order to improve the overall performance and reliability of your system. The different options for combining the disks are referred to as RAID levels. There are several different levels of RAID available depending on the needs of your system. One of the options available to you is whether you should use a Hardware RAID solution or a Software RAID solution.

     

    RAID Hardware is always a disk controller to which you can cable up the disk drives. RAID Software is a set of kernel modules coupled together with management utilities that implement RAID in Software and require no additional hardware.

     

    Pros and cons

     

    Software RAID is more flexible than Hardware RAID. Software RAID is also considerably less expensive. On the other hand, a Software RAID system requires more CPU cycles and power to run well than a comparable Hardware RAID System. Also, because Software RAID operates on a partition by partition basis where a number of individual disk partitions are grouped together as opposed to Hardware RAID systems which generally group together entire disk drives, Software RAID tends be slightly more complicated to run. This is because it has more available configurations and options. An added benefit to the slightly more expensive Hardware RAID solution is that many Hardware RAID systems incorporate features that are specialized for optimizing the performance of your system.

     

    For more detailed information on the differences between Software RAID and Hardware RAID you may want to read: Hardware RAID vs. Software RAID: Which Implementation is Best for my Application?


    There is only one thing a RAID  provides - more space.  Beyond that a RAID can’t help you with:

     

    1. Accidental deletion or user error
    2. Viruses or malware
    3. Theft or catastrophic damage
    4. Data corruption due to other failed hardware or power loss
    5. Striped RAIDs have a higher failure risk than a single drive

     

    The purpose of a RAID is to provide high speed mass storage for specialized needs like video editing, working with extremely large files, and storing huge amounts of data.

     

    If your array fails it means complete loss of data and hours of time to rebuild.  RAIDs degrade over time necessitating many hours of restoration.  And, if you don't know much about RAIDs then you really don't need one.

     

    You can use a RAID for backup.  But unless your backup needs involve TBs of data requiring rapid and frequent access, why bother?  TM works in the background.  It's not like you have to sit there waiting for your backup to be completed.  Furthermore, you're buying two drives possibly to solve a problem where a single drive will do.  And, one drive is less expensive than two.

     

    Ignoring overhead two drives in a RAID 0 (striped) array should perform about twice as fast. However, as the array fills up with files that performance will degrade.

     

    RAID was a technology that in it's time was meant to solve a problem.  Large capacity, fast drives were extremely expensive.  Small drives were cheaper but slower.  However, combining these cheaper drives into arrays gave faster performance and the larger capacity needed for data storage needs.  Thus, the reason why it's called Redundant Array of Inexpensive Drives.  But today you can buy a 3 TB drive with performance that's better than the 1 TB drives of two or three years ago.

     

    How to rebuild a software RAID mirror

    Disk Utility may not be able to verify or repair permissions on a software RAID set