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Thread: MBR vs. GPT

  1. #1
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    MBR vs. GPT

    Just added a new 6 Gb/S 2 TB drive to my Windows 7 Home 64 bit machine (http://www.newegg.com/Product/Produc...82E16822145475). Went into Disk Management to add the drive, it asks if I want to use Master Boot Record or GUID Partition Table as the partition style. Which should I choose? In searching, I see the GPT is generally used for 2TB or larger. What are the pros/cons of each? Disk will probably be used as storage only, though I may install the OS here as well.

    TIA

    Fred
    Last edited by Fred Forsythe; 06-24-2011 at 04:00 PM.

  2. #2
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    Not all versions of windows can utilise a GPT however the first sector of a GPT is called a Reserved MBR for certain backward compatibility reasons.

    The only versions of Windows that can utilise a GPT are
    64 bit versions - though even these can only boot from a GPT drive if the underlying hardware is Itanium based with an EFI BIOS.

    So it shouldnt really matter which one you choose especially if you are unlikely to boot from this drive and even more so if there is no EFI BIOS.

    With a functional GPT booting an appropriate operating system the main benefit is a much more flexible multiboot menu and other bits and pieces.

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    Thanks Paul, I'll go with the MBR ;-)

    Fred

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    You don't have to worry about using GPT until you go over 2TB. If you were to go over 2TB you would have to make it a GPT drive or windows would not see more than 2TB. Just a heads up for those wanting a 3TB drive or wanting to use more than 2TB total in a Raid array.

    And no, there is no converting, you have to wipe/rebuild the drive/array to go from one to the other.
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  5. #5
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    If you were to go over 2TB you would have to make it a GPT drive or windows would not see more than 2TB. Just a heads up for those wanting a 3TB drive or wanting to use more than 2TB total in a Raid array.
    The 2TB "barrier" is bound to start becoming an issue just as the various legacy BIOS "barriers" were in the not so distant past.

    With existing Windows and SPs one definitely needs 64bit Vista or above for this. I believe, but am not entirely sure, that an EFI based motherboard is also mandatory to support utilising volumes over 2TB with these 64 bit versions of Windows.

    I also understand that if you have mixed MBR and GPT hard drives in a system that this will enforce that MBRs (or the legacy MBR first sectors of any GPTs) are used throughout. Possibly this only occurs when one wants to boot from any particular drive but this too is not yet totally clear to me. In this regard if one already has a GPT hard drive in a system it would seem sensible to create GPT drives throughout.

    Yet another thing needs clarity and that is what the HDD sector size will be on any particular volume with a GPT. What I am really saying is I don't know if the change from a 512-byte to a 4-kilobyte sector is necessary in order to go over 2TB whatever the OS or Motherboard pairing is and indeed whether this would be enforced through all partitions or only on partitions greater than 2TB.

    We all need to be aware of the issues for the forthcoming future and I am sure all become clear in time.
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  6. #6
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    Quote Originally Posted by Paul Komski View Post
    With existing Windows and SPs one definitely needs 64bit Vista or above for this. I believe, but am not entirely sure, that an EFI based motherboard is also mandatory to support utilising volumes over 2TB with these 64 bit versions of Windows.
    GPT disks are supported by windows starting with XP 64bit, 32bit is not able to use them. XP cannot boot from GPT.

    Server 2003 64bit is able to boot from a GPT disk on a UEFI 64bit Itanium system.

    All versions of Vista, 7, and server 2008 can read/write GPT. Booting from GPT on vista and up requires 64bit and a UEFI motherboard. But not an Itanium system.

    So in a nutshell, XP64bit and later can use GPT disks, but you have to have a 64bit version of vista/7/2008 and a UEFI motherboard to boot from a GPT disks.

    Quote Originally Posted by jlreich
    And no, there is no converting, you have to wipe/rebuild the drive/array to go from one to the other.
    Let me clarify this. You can convert from MBR to GPT and GPT to MBR, it isn't like you are stuck once you choose. But, in order to do so you have to manually delete all partitions before it will even be an option. So the disk has to be either raw or contain no partitions.

    See here for more info on windows and GPT disks.

    Quote Originally Posted by Paul Komski
    Yet another thing needs clarity and that is what the HDD sector size will be on any particular volume with a GPT. What I am really saying is I don't know if the change from a 512-byte to a 4-kilobyte sector is necessary in order to go over 2TB whatever the OS or Motherboard pairing is and indeed whether this would be enforced through all partitions or only on partitions greater than 2TB.
    My understanding is that the 4KB sector is only required in order for disk manufacturers to go beyond 2TB. It has nothing to do with GPT or file systems. But because larger than 2TB requires both 4KB sectors (physical limitations I believe) and GPT (MBR limitations I believe) they go hand in hand. And yes, you can mix GPT and MBR disks in the same system to your hearts content.

    For instance my HTPC running XP 64bit has several 2TB MBR disks in it right now. I can add a 3TB disk and can, in fact am required to if I want to see above 2TB, make it a GPT disk. But the current MBR disks are just fine the way they are.

    One other things that is notable is that if you meet the other requirement to boot from a GPT disk stated above, the ESP (boot partition) or "Extensible Firmware Interface System Partition", has to be on drive 0. So no drive swapping with the boot disk, it has to stay in the 0 position. Although it is unclear to me if you can change the disk priority in UEFI setup so that a physically moved drive is set as the first disk and things will be fine or if the drive truly has to be on the physical port 0.
    Last edited by jlreich; 06-25-2011 at 09:01 AM.
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  7. #7
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    One thing that had perplexed me but which is now, I think, clear is that regardless of 512-byte or 4-kilobyte sectors the LBA addressing of such partitions is the same; in other words even though there are 8 legacy sectors per new sector the LBA value of the start of the second new sector will be 8 and not 1, then 16 and not 2, and so on.

    This is why 64 bit systems that can count beyond 2^32 (4294967296) are not limited to the 0.5 * 4294967296 = 2TB (2,199,023,255,552 bytes) limit imposed by 32 bit calculations.

    Since a legacy MBR can only store this same maximum value in its partition tables it is logical that a legacy MBR can only support individual partitions up to a maximum of 2TB - regardless of sector size. Or put another way not only will a 64bit OS be required but also a GPT in order to support partitions larger than 2TB.

    Many other issues, particularly multibooting, are likely to throw up all sorts of wobblies with such newer systems so any discussion of these issues is of much value.

    Since the LBA values of these large hard drives will not change it raises the question of exactly in what way these new sector sizes have been designed. I can only suspect that the normally hidden areas of a hard drive that do error-checking and so forth are organised on a 4kb and not on a 512byte basis. It is likely to mean that any read/writes must be done with a minimum of 4kb taking place - but whether this means that all files (or file fragments) must start on a 4kb boundary (as opposed to a legacy LBA value as dictated by the OS/File System) is not entirely clear.
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    It is interesting that I am currently looking at a 3TB Hitachi drive and looking at the specs it has 512b sectors. So at least at 3TB the 4kb sector size is not required. (note that this drive is on clearance, so probably manufactured before the agreed upon Jan 1st deadline for moving to 4kb sectors)

    I can only suspect that the normally hidden areas of a hard drive that do error-checking and so forth are organized on a 4kb and not on a 512byte basis.
    From what I remember that I read about it there is better error checking and such using the 4kb sectors. Also something about the way it is organized there is actually more available space for actual data using the 4kb sectors.

    Also looking at this brief from Hitachi it is good to note that Linux (check your particular distro), and apparently Mac 10.6 and up, do not require an EFI system to boot from a GPT disk. It actually names Ubuntu 8.04 and Suse both 64 and 32bit as not only able to use larger than 2.2TB but also able to boot from them.

    As usual it is windows that makes things harder than it has to be...

    As a side note, if you are using a controller card of any kind make sure to check its documentation and look for firmware updates before buying a larger drive.
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    So at least at 3TB the 4kb sector size is not required.
    I had assumed (always a bad thing to do) that it was these 4kB "units" that would enable the 2TB barrier to be overcome. This I now understand was misplaced because the same LBA addressing is used (1 LBA block per 512 bytes) whether or not the sector size is 512 bytes or 4 kilobytes. Thus to be able to access any hard drive PARTITION beyond the 2TB barrier requires a 64bit OS. Those drives utilising 4 kilobyte sectors deal with this at the firmware level and so the OS or file system in use is immaterial and is not "bothered" by the underlying hardware type.

    Since legacy CHS HDD addressing is rapidly becoming redundant it may be of some relevance that partition boundaries should be situated/placed on 4kB boundaries and not on the traditional cylinder (multiples of 63 legacy sectors) boundaries.
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  10. #10
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    Quote Originally Posted by Paul Komski View Post
    Thus to be able to access any hard drive PARTITION beyond the 2TB barrier requires a 64bit OS.
    I was going to disagree with that, but then I noticed you said "PARTITION beyond the 2TB barrier requires a 64bit OS".

    So you are saying a 32bit OS can see and use a 3TB drive, but not a partition that starts beyond the 2TB barrier? Can you clear that up a bit please? Can it see the whole 3TB if say it is one big partition, or if the last partition starts before the 2TB barrier?

    Or did you mean to say it can't boot from a partition beyond the 2TB barrier?

    I had assumed (always a bad thing to do) that it was these 4kB "units" that would enable the 2TB barrier to be overcome.
    So apparently it isn't required at the 3TB level, but it must be at some point because the manufacturers say that it is the larger sector size that will allow them to increase the size because it allows "increased areal densities". Then I wonder why we haven't yet seen a 4TB drive yet. Though I am sure it will come before long.

    I am still considering whether or not to get the 3TB that is on sale right now. I have been flipping back and forth between that and a 2TB mainly because of budget concerns. $120 vs $80..... But I would really like to get my hands on a 3TB to see how it acts on different OS's. I have xp/vista 64 and 32 bit as well as Linux 64 readily available to me to try it out on. And could throw in a live cd of 32 bit linux. I have the money, but I have been spending a lot cash this last week or so and it is kinda time to stop. We'll see...
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    So you are saying a 32bit OS can see and use a 3TB drive, but not a partition that starts beyond the 2TB barrier?
    I wish I knew for sure because what is theoretically possible and what is actually possible in real life requres an empirical answer. There are various links that give a similar but ambiguous answer such as from mingersoft and anandtech.

    What is clear is that for each primay partition referenced in an MBR and each logical partition referenced in an EPBR there are only available enough bytes to count to 2TB; (this is a physical limitation of a standard MBR/EPBR and nothing to do with 32 versus 64 bit OSes). There are two such entries for LBA block addressing; one for the starting position of the partition on the drive and one for the size of that partition.

    What is not so absolutely clear is if the start of the partition can be "found" (ie it is under 2TB from the start of the drive) whether or not it matters if the end of the partition must also be within the 2TB barrier on the hard drive or whether as long as the Partition Boot Sector resides within that extent it can address a further full 2TB or not.

    This is complicated by the fact that this so-called "hidden sectors value" (the value that indicates the start of a partition) resides not only in the first positional record of an MBR/EPBR but which is also to some extent mirrored within the PBS itself. They are exactly mirrored on primary partitions but the situation differs under Linux and Windows for logical partitions; under windows the hidden sectors value of the PBS relates to the start of the extended partition whilst under linux it relates to the start of the hard drive (and which is why without tweaking the PBS value with a hex editor) it is impossible to directly boot up a logical drive under windows when using any third party boot manager that has supplanted the MBR.

    I can only guess that using a 32 bit OS will allow one to utilise up to 4TB of a hard drive as long as the start of the last partition is within the 2TB barrier and possibly only if that last partition is a logical partition with the start of the extended partition being just prior to the 2TB barrier.

    Without reading a definitive answer somewhere or being able to experiment for myself I can only use applied mathematics to give a logical answer. It's surprising that it is so hard to find a definitive answer since enterprise users have been using huge RAID volumes for some time and there is really very little difference between a large RAID and a large HDD, when such geometry comes into play.
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    The only thing I can say with absolute certainty is I have a coworker that has an MBR based 3x1TB drive raid 5 setup for his file server running windows 7 64bit ultimate on a real raid controller ($150 range) and he added a fourth 1TB to the array to increase his capacity and windows only showed 2.2TB in disk management. As you can imagine he was rather disappointed at a 200MB increase.

    I told him he would have to convert the disks to GPT, but of course that is not an option because he doesn't have enough space anywhere else to store the data on the array in order to wipe the drives and start over so he can convert. So he is going to buy another raid card and start a new array with GPT disks.

    I am sure this type of scenario has played out many times because it just wasn't in anyones mind abut the 2TB barrier with MBR disks. I knew of it but I didn't even think about it when he mentioned he was going to add another disk to his array.
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    2.2 TB (being 2.0 TiB) is exactly the limit of an MBR entry.

    What is not quite clear is that after creating a 4 TiB (4.4 TB) RAID-5 array (with 1/4 of data lost through redundancy) as to whether the potentially max. available 3 TiB (3.3 TB) is restricted because there is just one partition or not - and indeed if multi-partitioned just what did the partitioning. If only one large partition it would also be very interesting to know what would be the outcome if there were two 1.65 TB (1.5 TiB) partitions created on it.
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    Single partition created by disk management originally, with the array rebuilt on the fly by the raid card when the fourth drive was added.

    Data only, OS resides on another drive not in the array.
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    A single partiton referenced from a legacy MBR can only be 2TiB even for a 64bit OS unless something akin to drive overlay or specialised drivers were in place at the time of creation or enlargement.

    One must wonder just what the RAID software did when enlarging "on the fly" - it probably just enlarged the size of the array (assuming the RAID software can deal with 64-bit geometry). It sounds very likely that the 200MB "increase" was just filling-out the 32bit max from 2TB to 2TiB - but it is also unclear whether the 2TiB is the reported size of the HDD or of the original partition having also been enlarged in parallel (and which would I think be unusual).

    If the RAID BIOS should happen to be limited to 2TB then this would, of course, be the maximum that it could report to the 64bit OS.

    It sure is a tricky area.
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    I just talked with him to make sure my facts are straight, fortunately he was sitting at the system when I called. The array is presented as a single large drive to the OS. After he added the fourth drive he said disk management shows 2794 GB total, so it seems it is actually seeing the whole array, but when he went to increase the partition to take up the unallocated space it only let it to go up to 2048 GB. [He doesn't remember exactly what size it was before.] He said when he r-clicks on the drive or otherwise goes to the options for the drive everything is grayed out.

    He said went into the raid cards software and simply added the drive to the array.

    He seems to think that if it was a dynamic disk he could use all 2794 GB. He said he was going to convert it, but as I mentioned above the option is grayed out. I don't know much about dynamic disks so I couldn't confirm or dispute his thoughts.

    He said the raid controller card (Rocket Raid 2300 - 4ports) supports up to 16TB and 64bit LBA for larger than 2TB per volume.
    Last edited by jlreich; 07-05-2011 at 07:17 PM.
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    Thanks - very interesting.

    The 2974 GB is almost certainly (to be pedantic) 2974 GiB since 1/3 of 2974 = 931 and 931 GiB = 1000 GB (10^12) which is the normal size of retailed 1TB hard drives. So we are agreed that the 64 bit OS can report the full size of the array in disk management.

    it only let it to go up to 2048 GB
    Pedantically again, 2048 GiB (2 TiB) is the maximum for 32 bit calculations and MBR partition table space. So if this has been "maxed out" there is no room left to begin a second partition prior to the limit. What would be most intersting to me would be the scenario in disk management if the first partition was say 1.5 TiB - and indeed what any third party partitioning tools might allow one to do or see.
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    This might be a good moment to elucidate a little on how this maximum value is played out from an MBR perspective - for anyone that is interested and indeed for my own reference.

    The four available bytes of an MBR partition table entry denoting the size of a partition by the number of 512-byte LBA sectors it contains can be represented literally as the 32 bits:
    11111111 11111111 11111111 11111111
    or using hex as:
    FF FF FF FF
    and which in decimal is:
    4294967295
    which including zero is 4,294,967,296 possibilities.

    Now 4,294,967,296 = 2^32
    and since each sector has 512 bytes (2^9)
    the total bytes addressable is thus 2^32 * 2^9 = 2^41 = 2,199,023,255,552
    and 2,199,023,255,552 = 2.0 TiB or approx 2.2 TB.

    In the days when the kilobyte and kibibyte first came on the computing scene the difference between 1000 and 1024 bytes seemed to be somewhat negligible but when this difference is perpetuated in a geometrical manner we have now arrived, at the terabyte level, where the difference between a terabyte and a tebibyte is some 10% and that does lead to a lot of confusion particularly with the purchasing public and when exact geometrical parameters are discussed.
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    That's a nice way to lay it out Paul. At least it works well for me.

    Seeing that the partition table entry represents how many sectors the partition takes up, wouldn't simply changing the sector size from 512bytes to 4kb (advanced format) allow for larger single partitions for a 32bit LBA? In theory 8x larger, or up to 16TiB?

    I actually think I read something to that effect at some point but didn't really understand the significance of it until now.

    We know that the issue isn't modern file systems. I also find it fascinating that windows requires an EFI "BIOS" in order to boot from a GPT disk, but Linux does not, even 32bit Linux.
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    wouldn't simply changing the sector size from 512bytes to 4kb (advanced format) allow for larger single partitions for a 32bit LBA? In theory 8x larger, or up to 16TiB?
    Before looking at this issue more carefully I had assumed that the change to 4kB "sectors" would have meant at least an 8-fold increase in the amount of data that could be accessed - even by 32 bit systems.

    For the moment this is not the case because whether there are 512-byte legacy sectors or 4-kilobyte new sectors the LBA addressing is the same: one LBA per 512 bytes of data; thus there are 8 LBA blocks per new 4kB sector and not just one. It is not a scenario equivalent to "file allocation units" as in the old DOS days.

    In fact such file allocation units or cluster sizes still persist under windows file systems to this day. But the number of such file allocation units or clusters or whatever else you want to call them are still addressed on a 512-byte per LBA basis.
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    Help to start using BiNG. Some stuff about Boot CDs & Data Recovery Basics & Back-up using Knoppix.

  21. #21
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    Quote Originally Posted by Paul Komski View Post
    whether there are 512-byte legacy sectors or 4-kilobyte new sectors the LBA addressing is the same: one LBA per 512 bytes of data; thus there are 8 LBA blocks per new 4kB sector and not just one.
    Ok, then it looks like for now at least the 4kb sectors are no help for MBR disks.

    I did just ordered the 3TB drive. Today was the last day of the sale so I had to make up my mind. I don't expect to get it until early next week.

    Before I put it into its intended use I plan on trying various sceneries on various system/OS's to see what happens. I am actually glad that it is 512b sectors as that is one thing that will not confuse the issues.

    So far what I have in mind -

    Make it an MBR disk, partition at ~1.5TB and see what I can do for the second partition. Try this on XP 32bit, XP 64bit, vista 64, Linux 64/32 and finally try via USB adapter on my wifes laptop with vista 32.

    Also interested to see what BiNG thinks of it. Still running the 1.x version.

    Then convert to GPT and do it all over again just to see how the various OS's treat it as GPT.

    Anything else you can think of that would be good to try or any tools to run on it?
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  22. #22
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    I did get the 3TB drive Monday, but a close family member passed away and as you can imagine I have been pretty busy since.

    Got to messing around with it today and here is what I have so far -

    Hooked up the drive to XP32bit -

    BIOS showed 3000 GB
    BiNG 1.86a 764429 MB
    XP32 disk management 746.51 GB
    Made a 500GB partition, showed as 488.28 GB with 258.23 GB remaining as expected.

    Per the instructions on drive packaging downloaded Hitachi GPT disk manager that says it works with all version of windows xp32 and up allowing the drive to be fully utilized. Ran the tool without converting to GPT, it showed the drive split into two, 2047.9GB/746.5GB. In that order. Actually using the tool to convert to GPT will come later.

    ---------------------------------------------------

    Hooked up to the system in my sig -

    BIOS 750GB, but now that I think about it I will have to double check that because I think I looked at the other Hitachi drive in my system that is actually 750GB. Oops!

    Was not able to check BiNG in this system because all SATA ports are used and I had to pull a drive in order to hook up this one, so drive order was messed up temporarily. EMBR missing etc...

    Vista 64bit disk management initialized as MBR had same split as the Hitachi tool in XP32, 2048GB/746.51. Partitioned 1.25TB at beginning of drive, that left the remaining space of the first section of 2048GB available but unable to do anything with 746GB section.

    Deleted partition but no option was present to convert to GPT in disk management , tried to install the Hitachi GPT tool but it told me windows already recognized the drive correctly and I didn't need to install the tool. But I was able to run DiskPart in command prompt. Was able to run the "clean" command to wipe the MBR/GPT, "convert" command to go back and forth from both MBR and GPT without any issues whatsoever. I had disk management up in the background and could so the changes immediately as I ran the commands.

    Once converted to GPT I was able to partition using the whole drive or multiple partitions however I wanted.

    -----------------------------------------------

    Booted to a Live CD of Ubuntu 10.04 32bit. And this is where it gets really interesting...

    GParted shows the full disk at 2.73 TiB. Created an MBR and it remained as a single 2.73TiB drive.

    Tried creating a partition of the entire drive both as NTFS and ext4 and got an error stating that the partition size "exceeded the msdos imposed maximum partition table size of 4294967295 bytes".

    Created a 1.25 TB NTFS partition at beginning of drive, no issues. Tried to create the remaining space of 1.54TB as ext4 but got this error.

    GParted 0.5.1

    Libparted 2.2
    Create Primary Partition #1 (ext4, 1.54 TiB) on /dev/sde 00:00:01 ( ERROR )

    create empty partition 00:00:01 ( SUCCESS )

    path: /dev/sde2
    start: 2560005945
    end: 5860528064
    size: 3300522120 (1.54 TiB)
    set partition type on /dev/sde2 00:00:00 ( SUCCESS )

    new partition type: ext4
    create new ext4 file system 00:00:00 ( ERROR )

    mkfs.ext4 -j -O extent -L "" /dev/sde2

    mke2fs 1.41.11 (14-Mar-2010)
    /dev/sde2 is apparently in use by the system; will not make a filesystem here!

    ========================================
    But here is the kicker, I create the last partition as NTFS and it works! I mounted/unmounted the volumes, I opened them, no problem. I tried various sceneries with NTFS and ext3/4 as first and last partition and ext3/4 worked fine as first partition, but nothing would work as second partition except NTFS.

    Converted to GPT and tried to create a single 2.73 TiB partition and would get an odd error that indicated rebooting may be needed. Didn't try rebooting yet, but somehow I don't think it will work in 32bit without splitting it up and keeping the first partition below 2 TiB. But I will try it to be thorough.

    Converted back to MBR, created the two partitions again, both as NTFS. Booted back into vista 64 and two explorer windows popped up automatically, one for each partition. Computer and disk management both show the entire drive and both partitions correctly.

    I plan on throwing the drive as it is now back into the XP32bit machine and see if it does the same as Vista64 did, as well as several other tests I have in mind.


    Edit- would like to also mention that the drive is a SATA 3 drive, and I have no Sata 3 ports on any of my systems as of yet. So for those wondering about backwards compatibility well there you have it.
    Well, that's it for now. I will continue my experiments tonight or tomorrow. Until then if you have anything specific you want me to try out let me know.
    Last edited by jlreich; 07-16-2011 at 02:50 PM.
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  23. #23
    This is a great thread that should be stickied - the 2TB barrier is going to become a major issue, just like 8.4gb barrier back in its day.

    As far as I'm concerned, I'm out of luck with this one. I own a 2008-vintage Abit AN52 board, which is no longer supported since Abit went out of business shortly after this board was designed. A shame really, as it's an amazing board which gives a 30% overclock rate out of a dualcore Athlon 64 for a killer system, even by 2011 standards - I'm obviously going to keep using this computer for a very long time to come.

    Anyways, I am tempted to buy a new disk drive but there is no way the BIOS of this board would support anything over 2TB. I don't need to boot off the new drive (I have my 120gb PATA clunkers for that) but based on what you guys have discussed, I now realize that there is no way my board could talk to disk drive sectors located beyond the 2TB mark.

    The good news is that the board has a few vacant PCI and PCIe buses, so I might invest in a SATA controller card with its own upgraded BIOS for large disk drives. The manufacturers of disk drive controller cards are probably going to make a fortune out of this mess.

  24. #24
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    Quote Originally Posted by kiosk View Post
    I am tempted to buy a new disk drive but there is no way the BIOS of this board would support anything over 2TB.
    Not necessarily true. It won't be able to boot windows, but I can't see any reason why it wouldn't work as a data drive or be able to boot Linux. The board is not that old. And I haven't read anything as of yet about motherboards not being able to handle it. The only exception being the need of a UEFI BIOS in order to boot windows. But that is a windows issue. I will confirm it tomorrow, but Linux is supposed to be able to boot without the need for a UEFI board.

    The good news is that the board has a few vacant PCI and PCIe buses, so I might invest in a SATA controller card with its own upgraded BIOS for large disk drives.
    WD has a 3TB drive or two that comes with a PCIe x1 SATA 3 controller card. But again, I can't see any reason why you would need one other than trying to get SATA 3 speeds, which won't happen with a 5400 RPM green drive like I have anyway.

    But these are the kinds of questions we are trying to answer. Unfortunately I don't have an older board with SATA ports to try it out on. The oldest one I have is the one in my sig. Well, I actually do have an old socket A board with two SATA 1 ports running my firewall machine, but I really can't have my firewall machine (internet for my entire network) down long enough to test it. Everything else I have that is older doesn't have SATA ports.

    I would also like to add that while the spec sheet for my drive says it has 512 byte sectors, I was reading some other docs from Hitachi and it seemed to indicate that all their 3TB drives have 4KB sectors but the firmware presents itself as 512 in order to fool the system. But it wasn't very clear to me if that is really the case for all their larger than 2.2TB drives, or if they were referring to a particular series.
    Last edited by jlreich; 07-16-2011 at 09:20 PM.
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  25. #25
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    Put the drive as GPT with two NTFS partitions in XP 32 and it still showed only a 746.52 GB partition, unallocated. It did show in my computer but when clicked on it asked to format it. Which I did not do.

    Ran the Hitachi GPT tool, interestingly showed as -

    unallocated 746.5 GB
    local disk (invalid) 1573.8 GB
    local disk (ntfs) 1220.7 GB

    (In windows disk management it showed the 746 GB section at the end of the drive and the rest at the front.)

    Ran the convert to GPT option, even though it already was GPT, had to reboot a couple of times I believe simply because of the existing partitions or it likely would have been just one reboot. Once that was done created a new single large 2794.3 GB NTFS partition in disk management without any issues. So the Hitachi GPT tool does make it work in XP 32bit. But making it GPT and formatting from Linux does not work for XP 32bit as it did for vista 64bit. Must use the GPT tool.

    ---------------------

    Ubuntu 64bit Live CD -

    Left the disk in state above as GPT single NTFS partition. Everything worked great. MBR whole disk 2.73 TiB single NTFS/FAT32 ext4/3 partitions without issue. Two MBR mixed format partitions, no issues.

    And of course GPT had no issues. Only thing to note is ext4 took 12 and ext3 15 minutes to create while NTFS/Fat32 took only seconds. But all went well.

    --------------------------

    Ubuntu 32bit Live CD -

    Left disk as GPT ext3 single whole disk partition, no issues. Ran the tests again as before with no issues this time, so perhaps a reboot would have done it. Perhaps the volume wasn't unmounting correctly for some reason or something... Still couldn't make MBR single partition past the 2 TiB barrier (expected), but splitting drive worked fine for the various file formats including ext3/4 and Fat32.

    Wanted to install Ubuntu 32bit to drive to make sure it can boot from GPT but I am out of time for now.
    8.1 Pro 64bit
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    "The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
    - Albert Einstein

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