SSDs are incompatible with GPT partitioning?!

Discussion in 'Memory and Storage' started by techvslife, Feb 22, 2012.

  1. akc

    akc Junior Member

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    1. So no one has duplicated techvslife's corruption issue? (though i believe it's real). How about uninstalling Intel's drivers to rule out?

    2. As an aside: As a non-Mac owner I've heard Apple does use Samsung 830 SSDs in their recent laptops, and that Apple supports some form of GPT. Wouldn't that combo present with problems?

    3. I'm glad I haven't gone ahead to play with GPT on my 830.... (though I'll look into whether Plextor has done better).
     
  2. Oubadah

    Oubadah Golden Member

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    I haven't tried GPT on the 830 yet, but I recently formatted my Crucial M4 with GPT:

    [​IMG]

    ^ I don't even know how to interpret the results - it it corrupted?
     
  3. Insert_Nickname

    Insert_Nickname Platinum Member

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    I have run the 830 for 4 months with GPT, without any issues what-so-ever...
     
  4. Coup27

    Coup27 Platinum Member

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    If you read the whole thread then you'll see that in normal use you won't see any issues. The issue came about when somebody checked the integrity of the GPT structure and found it to be currupt.

    From my limited knowledge of the subject, GPT contains information at the end of the disk which would allow it to be rebuilt from this information. The 830 possibly overwrites this information during use but unless you ever attempt to rebuild a GPT disk with the backup header than you will never see there is a problem.
     
  5. Insert_Nickname

    Insert_Nickname Platinum Member

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    No, you misunderstand. The GPT structure is perfect here, no corruption. Mine might be a newer revision then the OPs...?
     
  6. Coup27

    Coup27 Platinum Member

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    My bad. I don't know then. There will be no changes in the 830 throughout its life, they'll all be the same. I was able to repeat the OP's problem when I tried on my 830 but with no official word from Samsung on the subject we never really got to the bottom of it.

    Be interesting to see if the 840 & 840 Pro are officially supported on GPT.
     
  7. AdamK47

    AdamK47 Lifer

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    My Vertex 4 was running MBR until recently. Converted it over to GPT while retaining my Windows install and other data. No problems so far.
     
  8. greenturtle99

    greenturtle99 Junior Member

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    I have been following this thread for some time and had nothing to contribute. However, I want to confirm I have identical problems since I started my new build in late summer. I have two Samsung 830 SSDs that have only the EFI boot partition and Linux ext4 partitions. I have left substantial unpartitioned space (40GB) on each SSD for now since I have been unable to find out exactly how Samsung overprovisions the SSDs. Version 3.2 of the Magician software has been no help.

    I have a Windows 7 installation on an HDD primarily for diagnostics since Linux is not officially supported on my Asus P9X79 WS. Mostly I run VMs for daily use of guest OSs. Usually, the back up table corruption happens on the SSD that does not have the EFI boot sector but also happens occasionally on the other SSD. I have had no operational errors otherwise and I keep copies of the GPT partition tables on HDD as well as backups (remember to back up your EFI partition). But low level corruptions (even of backup tables) are always irritating.

    This has been an education in the state of implementation of EFI, GPT, motherboards and SSDs. I have followed all the suggestions in the thread, very slowly and iteratively, to try to isolate the problems (boy do I dislike intermittent failures). It has made me very skittish about SSDs that do not list what they support and don't (usually very incomplete and impossible to find out even from the vendor). I bought Samsung because it was one of the few consumer SSDs that claimed support for Linux. I hope the release of Windows 8 will push the maturity of EFI and GPT.

    But let me confirm the problem exists.
     
    #33 greenturtle99, Dec 11, 2012
    Last edited: Dec 11, 2012
  9. Amnesia1187

    Amnesia1187 Junior Member

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    What exactly are you doing to see the corruption? As it's a different controller the problem may not exist at all on my 840 pro, but I gave been validating my disk in gDisk periodically to check for any issues. How frequently is it happening for you? Any errors or anything in your System Event Logs?
     
  10. greenturtle99

    greenturtle99 Junior Member

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    I am using gdisk too. I have not found any correlation in the system logs. The only way I find it is periodically running gdisk. There is some correlation between dual booting into Windows 7 but it can still happen in Linux (Ubuntu 12.04) without ever running Windows 7 natively. I have been ramping on using GSmartControl (smartmontools - Samsung 830 is in their database), trim in Linux.

    I happens perhaps once a week but it really random with several in quick succession and and then I go a week or two. Are you seeing this on the 840 pro's too? The should be up to date on EFI/GPT because of the Windows 8 rollout (I hope). I have not stayed in Windows 7 long enough to correlate anything to this corruption.

    In my fstab:

    UUID=randomhex / ext4 defaults,relatime,discard 0 1
    UUID=randomsmallhex /boot/efi vfat defaults 0 1

    I understand the "discard" is important to maintain performance by enabling trim (on supported file systems). I am doing maintenance manually once a week since I don't know the source of the errors. I have not tried changing the EFI partition to "discard".

    This weeks experiment is to turn off the Legacy bios compatibility in the Asus firmware making it pure EFI for a long term test (at least a couple of weeks). I gave up doing quick changes and I am being very methodical now.
     
    #35 greenturtle99, Dec 11, 2012
    Last edited: Dec 11, 2012
  11. wpcoe

    wpcoe Senior member

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    Interesting. Recently I experimented with Win8 and installed it in an EFI/GPT configuration, but Win8 could *not* see/access my other SSD or HDD when they were MBR.

    Only after I converted my second SSD to GPT could Win8 in an EFI/GPT configuration see/access it.

    I ended up reverting to BIOS/MBR because I didn't want the hassle of shuffling data off of my 1TB HDD to convert it to GPT.

    Is there something unique to Win8 that would prevent me from seeing/using MBR drives when I have an EFI/GPT Win8 boot drive?
     
  12. geohei

    geohei Junior Member

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    Hi.

    I found this thread through Google. I have a similar problem, but no data corruption (yet). Can someone confirm that the problem described below is the same one as discussed in this thread?

    --

    I installed Windows 7, Ubuntu 12.10 and Arch Linux (in that order) on a WD 1TB HDD using UEFI (Gigabyte Z77 motherboard) and GPT for the HDD. Everything worked fine.

    Now ... when I use the Samsung SSD 840 PRO Serie (lastest firmware DXM04B0Q is on) and start installing Windows 7, the installer shows already that Windows 7 can't be installed on that disk because no MBR ... (can't remember the exact phrasing). But then, when I continue the installation, all works fine. EFI partition (100 MB), msftres partition (128 MB) and the Windows 7 partition is installed. Later on I proceed with Ubuntu and Arch Linux ... all works just fine!

    GParted shows that the device uses GPT ... so all good!

    But ... when I reboot the system, the UEFI Boot Manager doesn't show the SSD to be able to start using UEFI. It only shows the BIOS type entry.

    The actually shown UEFI Boot Manager BIOS start entry is: "P0: Samsung SSD 840 PRO Series"
    The UEFI Boot Manager UEFI start entry should be: "UEFI: Samsung SSD 840 PRO Series"

    The second one, I don't see.

    For the previously, for testing purpose used HDD, I saw:
    The shown UEFI Boot Manager BIOS start entry is: "P2: WDC WD1000FYPS-01ZKB"
    The shown UEFI Boot Manager UEFI start entry is: "UEFI: WDC WD1000FYPS-01ZKB"
    That's the way it should be and also what I expected for the SSD to see.

    Honestly, I have no clue where to start to look for the error.

    Is it the motherboard UEFI firmware which doesn't support Samsung SSD UEFI start?
    Is it the Samsung firmware?
    Is it something I forgot / didn't know to do prior installing the OSs?

    Any ideas?

    Many thanks!
     
    #37 geohei, Jan 20, 2013
    Last edited: Jan 20, 2013
  13. geohei

    geohei Junior Member

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    Update ...

    I ran one more test and installed Windows 7 again, and the error message that Windows 7 can't be installed on that SSD didn't reappear. No clue why!

    But then, I kept on testing. I noticed that "UEFI: Samsung SSD 840 PRO Series" showed after Windows 7 was installed AND the BIOS was reflashed (same firmware version, F14). When I selected "UEFI: Samsung SSD 840 PRO Series", Windows 7 started properly. However when rebooting, I noticed that the "UEFI: Samsung SSD 840 PRO Series" entry in UEFI Boot Manager was replaced by "Windows Boot Manager".

    So in fact, what I described in the previous article seems to be normal.

    I don't have deep knowledge about the UEFI Boot Manager mechanisms, but the replacement of the SSD UEFI entry seems to be done on purpose by the Windows boot loader.

    Hence, I believe I can safely use the system as it is now, without any worries about UEFI/GPT incompatibilities.
     
    #38 geohei, Jan 21, 2013
    Last edited: Jan 31, 2013
  14. Coup27

    Coup27 Platinum Member

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    Nothing that I am aware of. My Windows 7 test installation detected my MBR HDD absolutely fine.

    I am more than likely going to give Windows 8 a wide birth on the desktop front.
     
  15. gillesv

    gillesv Junior Member

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  16. LeetMiniWheat

    LeetMiniWheat Junior Member

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    Sorry for bumping old thread but I'm still curious if this is an issue on older SSDs like the Samsung 830. I emailed Samsung but I'm not sure I trust their answer. I quoted their previous statement about MBR being recommended after they initially assured me GPT was safe.

    Yet their final firmware release was dated january 2012... if it's indeed a firmware issue with their controller chip doing garbage collection, then it's probably not fixed? They seem to be blaming old motherboards?

    I noticed they have Mac firmware, last updated in 2014 but it has the same firmware version number. Macs install to GPT by default AFAIK, so perhaps this one doens't have the GPT bugs? Couldn't get a straight answer from Samsung about the firmware differences or if this GPT bug still exists. I'm also curious if the controller chip even properly recognizes free space for garbage collection, overprovisioning, and TRIM commands on GPT formatted discs.
     
    #41 LeetMiniWheat, Jan 23, 2016
    Last edited: Jan 23, 2016
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