Weird hard drive partitions


  1. Posts : 13
    Windows 7 Home Premium 64bit.
       #1

    Weird hard drive partitions


    I've recently built a new system and saw something I couldn't figure out.

    This is my system -



    see the arrows pointing at the very skinny partitions?



    What in the world are those and how do I get rid of them?
      My Computer


  2. Posts : 2,752
    Windows 7 Pro x64 (1), Win7 Pro X64 (2)
       #2

    Your screenshots are not readable. Too small, even when using the "+" on Photobucket.

    Can you simply state how large those small areas are?

    And how did you format these disks 3, 4, 5 and 6? Some software product? Windows? Are these brand new and this is the first time you're using them? Where did the data that's on them come from?

    Did you never have the small areas before now?

    Are these drives from some old system, which used to have Windows on each one? Or are they brand new?

    Also, are the partitions on disks 3, 4, 5 and 6 "logical" or "primary"? I ask because logical partitions reside inside an "extended partition" on the drive, and that "extended partition" involves just under 8MB of disk space of overhead in front of it (to provide the boundaries of the extended partition and other info about the extended partition). Are these 8MB areas? Sorry... can't see it.

    Sorry... cannot see this for myself because it's just too small to read.

    EDIT: just managed to make out that your "problem" drives are formatted as GPT. I confess I know next to nothing about this, but I have a very strong suspicion that your little areas are directly related to the fact that these drives were partitioned as GPT, rather than MBR. Are they larger than 2TB, in which GPT would be needed? Or are they 2TB or smaller, in which case MBR would be usable?
      My Computer


  3. Posts : 13
    Windows 7 Home Premium 64bit.
    Thread Starter
       #3

    These are all brand new WD drives that were formatted before anything was transferred to them using windows 7. Numbers 3 & 4 are 128mb - #5 is 100mb and is the c: drive. It says "system reserved". #6 says 7.65 mb unallocated. I've never seen anything like this before. Drives 3 & 4 are 3 TB drives - drive 5 is an SSD 256mb and drive 6 is a 2 TB drive. Drives 3 & 4 are GPT but drives 5 & 6 are MBR



      My Computer


  4. Posts : 2,752
    Windows 7 Pro x64 (1), Win7 Pro X64 (2)
       #4

    cquinn said:
    These are all brand new WD drives that were formatted before anything was transferred to them using windows 7. Numbers 3 & 4 are 128mb - #5 is 100mb and is the c: drive. It says "system reserved". #6 says 7.65 mb unallocated. I've never seen anything like this before. Drives 3 & 4 are 3 TB drives - drive 5 is an SSD 256mb and drive 6 is a 2 TB drive. Drives 3 & 4 are GPT but drives 5 & 6 are MBR
    Ok.

    Your drives 3 and 4 are larger than 2TB (I am guessing they're 3TB, minus formatting overhead, yielding a net of 2.73GB available NTFS capacity as is shown). So they have to be formatted GPT. And I would guess the 128MB overhead there is for GPT. I don't know the color scheme of the partition types but I'll guess green means "primary", and blue means "logical". Anyway it appears the 128MB is nothing for you to worry about... it's simply GPT overhead, and does not correspond to any drive letter. Think of it as invisible to you.

    Drive 5 is your system drive, which contains both Boot Manager as well as Windows. Since the drive is smaller than 2TB it is formatted using MBR. The little sliver you're questioning is actually the standard 100MB "system reserved" partition that Windows creates when you do a fresh install on a brand new empty drive. The Windows installer also installs Windows 7 itself into the second partition on that drive which you see as C, and which unless you override the default will be allocated to consume the entire rest of the available drive capacity... just as you see. That's where Win7 lives. This little 100MB "system reserved" partition contains Boot Manager (along with the Boot Manager Menu data, in the case where you might have multiple Windows systems to optionally boot from), and is also marked "active". That's how the BIOS knows to go to that little partition to locate and kick off Boot Manager when you boot the machine. Absolutely standard, and there's nothing you need to do about it. Again, no drive letter, and just think of it as invisible. It's critical to the boot process.

    Drive 6 is a 2TB drive (so it is MBR, rather than GPT which is only used for drives larger than 2TB) which appears to have been formatted as one large "logical partition". That's what I was describing in my previous post, where there is a 8MB fixed overhead to define the "extended partition" on the drive, inside of which you can then have one or more "logical partitions" defined. In your case you have only one, but the 8MB overhead for the "extended partition" is still required, no matter whether you have one or ten logical partitions inside of that "extended partition". 8MB is the right amount.


    So... everything looks right to me. It's all perfectly explainable.

    Out of curiosity, what is the brand of your SSD? If it's a Samsung they have Samsung Magician software which can improve performance of the drive. One of the improvements requires "over provisioning", i.e. leaving just under 10% of the overall drive capacity unallocated to any partition but available for Samsung Magician. Just curious if this is applicable to you.
      My Computer


  5. Posts : 7,055
    Windows 7 Home Premium 32 bit
       #5

    The 128MB partitions in the 3TB GPT drives are known as MSR (Microsoft System Reserved) partitions.

    "What is a Microsoft Reserved Partition (MSR)?
    The Microsoft Reserved Partition (MSR) reserves space on each disk drive for subsequent use by operating system software. GPT disks do not allow hidden sectors. Software components that formerly used hidden sectors now allocate portions of the MSR for component-specific partitions. For example, converting a basic disk to a dynamic disk causes the MSR on that disk to be reduced in size and a newly created partition holds the dynamic disk database."

    Windows and GPT FAQ (Windows Drivers)

    MSR is required only on a GPT bootable drive. On GPT drives used as secondary data drives, the 128MB MSR partition is not required. One can safely delete that partition and annex that space to the succeeding partition without leaving a gap
    (If you leave a gap as unallocated, your partitions will not be compliant with the UEFI standard and some disk utilities may see the gap as the end of useful data, and then decide to overwrite any partitions after the gap!) So annexe it to the succeeding partition. No gaps permitted on a GPT drive.

    Windows Disk Management will not show the 128MB MSR partition. Other partitioning/formatting software may show where you can delete and then merge/extend.
      My Computer


  6. Posts : 13
    Windows 7 Home Premium 64bit.
    Thread Starter
       #6

    thanks for the help. have sorted one drive and will tackle the others over the next few weeks. thanks again
      My Computer


  7. Posts : 13
    Windows 7 Home Premium 64bit.
    Thread Starter
       #7

    OK - I've sorted out all the non bootable drives



    Now I wonder if I use the same procedure to deal with my c: drive. Obviously I don't want to corrupt my OS.
      My Computer


  8. Posts : 2,752
    Windows 7 Pro x64 (1), Win7 Pro X64 (2)
       #8

    cquinn said:
    OK - I've sorted out all the non bootable drives

    Now I wonder if I use the same procedure to deal with my c: drive. Obviously I don't want to corrupt my OS.
    I understand what you did. I don't know what software you're using to display these drives and why the colors have changed on the GPT drives.

    But for sure, there's nothing wrong with your C drive that requires any change from what it is right now.

    (1) If a drive is formatted as GPT, it may or may not have that 128MB overhead "MSR" (as was explained earlier by Jumanji). So you've apparently deleted that optional space on the two non-boot data drives, and also enlarged the partitions on your two GPT drives Disk3 and Disk4 to annex that space on both drives.

    Good. There is no longer anything shown on those disks representing anything other than the G and H partitions themselves.

    (2) You have apparently converted Disk6 to now contain partition I allocated as a "primary" partition whereas originally it was allocated as a "logical" partition". Thus the normal 8MB "extended partition" overhead (required when you have one or more "logical" partitions allocated on the drive, inside of that "extended partition") would no longer be necessary.

    A "primary" partition does not have any overhead. So when you converted the original I from logical to primary, the original 8MB "extended partition" overhead would be available to annex into the I primary partition replacement, thus making 100% of the available formatted space on the drive available to I as you've shown.

    Good again.

    (3) Disk5 contains the standard 100MB "system reserved" partition (of which about 50MB is actually in use) which the Win7 installer will create for holding Boot Manager, whenever you install Win7 from scratch onto a new empty hard drive. It also contains the C (operating system) partition which will normally utilize all of the remaining available space on the originally empty drive unless you step in and alter the standard installation defaults.

    For example, if you had wanted a smaller C and had wanted to make the rest of the drive i.e. to the right of C) available for a "data partition", you should have pre-partitioned the drive before installing Win7, allocating the "data partition" at the high end of the drive and leaving a reduced unallocated free space at the low end of the drive. This would have limited the eventual size of C to only use the reduced unallocated free space, although you still would have gotten the same small 100MB "system reserved" partition.

    If you look more closely at Disk5 (with either DISKMGMT.MSC or Partition Wizard or other similar software) you'll see that the small 100MB "system reserved" partition is marked as ACTIVE. That means the BIOS will go there (to the "active" partition on the drive) to find Boot Manager to kick off the rest of the OS boot process. So you can't just delete this 100MB partition without dealing with the need to have one partition on that boot drive marked as active and also containing Boot Manager.

    That's actually what Windows Repair will do for you if you absolutely wanted that extra 100MB added to your C partition and deleted the "system reserved" partition, thus making the system UN-BOOTABLE. Because the system is now unbootable, booting to the Windows installation DVD will offer Windows Repair to fix the problem. This would then reinstall Boot Manager into C, and mark it "active", thus restoring bootability to your system but without use of the "system reserved" partition space of 100MB. And then you could use some partitioning tools to enlarge C to the left, to annex that now available 100MB.

    But you'd really only be getting net about 50MB of new available capacity into C, since the same 50MB of content (i.e. Boot Manager) would now be in C (which is now the "active" partition for the BIOS to go to at boot time) instead of where it currently is inside of the currently "active" 100MB "system reserved" partition.

    ==> My recommendation is DON'T WASTE YOUR TIME. This 100MB "system reserved" partition (ACTIVE) is the standard way a newly installed Win7 system looks when installed onto an initially empty drive. It's simply 100MB, of which only 50MB is technically unused and actually available for C.


    As I mentioned earlier, if this SSD is from Samsung, I'd more recommend you consider "over-provisioning" (i.e. shrinking C so that there is about 23GB on the drive that is UNALLOCATED, to the right of C) and thus make that space available for use by Samsung Magician to improve SSD performance.

    Running Samsung Magician will suggest that option to you, and will also tell you the minimum size of that UNALLOCATED space it would require to satisfy "over-provisioning". Now you really have to decide about the tradeoff: (a) about 23GB unallocated that is theoretically usable in C but resulting in somewhat less than optimal performance of the SSD, or (b) keep it UNALLOCATED and optimize SSD performance.

    In my opinion you have so much other space available on your other drives that you might as well optimize SSD performance by "over-provisioning", thus removing about 23GB from use as part of C. But it's up to you... if this is a Samsung SSD.
      My Computer


  9. Posts : 13
    Windows 7 Home Premium 64bit.
    Thread Starter
       #9

    Thanks. Will leave it as is. Appreciate all your help
      My Computer


 

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