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Drive failed, all folders were duplicated, but I can't access data RRS feed

  • Question

  • I've been using Windows Home Server PP2 for several months with great success, but I just had a drive failure that shook my confidence in the whole system.

    I have duplication enabled on every shared folder, but when one of my drives failed I could no longer access a vast majority of the files in each folder.  Some were still accessible, however, and I was able to browse through the various directories just fine.  I just couldn't open/view/copy most of the files.  (These files happened to be all the photos and videos of our four month old, so my wife and I nearly suffered heart attacks.)

    In the network health screen, WHS showed file conflicts in each of my shared folders.  Before the drive failure there were no file conflicts and network health was nice and green.


    Shouldn't file duplication behave somewhat like RAID-1 when a drive fails and still let me open/copy/backup the secondary copy of the file?  If not, what did I gain by using file duplication?  I'd expect all sorts of network health warnings about the missing drive, but no interruption in access to my duplicated data.
    Wednesday, June 10, 2009 5:59 PM

Answers


  • 1. I attempted to access the files using robocopy and plain old windows explorer from an XP box and a Vista box.  In both cases, many files would not open although I could browse the shared folders' directory trees.

    2. I don't have it in front of me right now, but robocopy said something like the device is not ready and it couldn't read the file.


    This is because it is trying to access the files that are on the missing drive.


    3. I did not remove the hard drive from the console, but it was marked as missing.  Shouldn't WHS let me access the duplicate copy of the file in the event that one copy is on a missing drive?

    It seems awfully risky to remove the drive to restore access and have the Migrator potentially delete files that it can't find on the remaining drive for whatever reason.  In other words, all the file conflicts and the fact that I can't access any data doesn't give me great confidence that removing the drive from the console is going to do the right thing either.


    If duplication was enabled and you remove the missing drives, the alternate shadows will be promoted. The deletion it is refering to are the tombstones that point to files that were in non-duplicated shares on a drive that has been removed i.e. there is only one shadow. Files that are duplicated have two shadows a master and an alternate (secondary).

    If the second copy was on a file with a bad power supply, the master shadow is unaffected and will create an alternate shadow on the next migration pass. Also, if you remove the missing drive with the bad power supply via the console and plug the HDD into another PC with the new power supply, the file is available under the \DE path providing that no corruption took place on the drive due to the bad power supply.

    If the HDD with a bad power supply is plugged back in once a new power supply is attached, then this entire situation is resolved once the server is rebooted.

    Please see the Drive Extender Technical Brief for more information.
    Lara Jones [MSFT] | Program Manager
    Community Support and Beta | Windows Home Server Team
    Windows Home Server Team Blog
    Connect Windows Home Server
    Windows Home Server
    Thursday, June 11, 2009 12:31 AM
    Moderator
  • Lara,
    1. I attempted to access the files using robocopy and plain old windows explorer from an XP box and a Vista box.  In both cases, many files would not open although I could browse the shared folders' directory trees.

    2. I don't have it in front of me right now, but robocopy said something like the device is not ready and it couldn't read the file.

    3. I did not remove the hard drive from the console, but it was marked as missing.  Shouldn't WHS let me access the duplicate copy of the file in the event that one copy is on a missing drive?

    That depends on which copy of the data is missing.  If your alternate (second) shadow is on the drive that failed, you should still be able to open the file.  If, however, the primary (first) shadow is on the drive that failed, the alternate shadow needs to be promoted to primary and that won't happen until you remove the failed drive from the server.  (That's also why you can open some, but not all, of the files.)

    It seems awfully risky to remove the drive to restore access and have the Migrator potentially delete files that it can't find on the remaining drive for whatever reason.  In other words, all the file conflicts and the fact that I can't access any data doesn't give me great confidence that removing the drive from the console is going to do the right thing either.

    That's how it's designed to work.  What makes you think it's not "going to do the right thing"?  (If you're that worried about it, you could always shut down your server, disconnect each working drive and copy all of the data from all of the drives to another location.)

    Is there no way for duplicated shared folders to simply fail over to one copy when the other copy's drive goes missing for whatever reason?

    That's not how it works.  However, you could always suggest that on Connect.

    What if the second copy was on an external drive with a bad power supply?  I'd have to cross my fingers and completely remove the drive from WHS to access the files while I order a new power supply?

    Thanks,
    Josh

    • Marked as answer by Josh Christie Thursday, June 11, 2009 8:44 PM
    Thursday, June 11, 2009 12:37 AM
    Moderator

All replies

  • I've been using Windows Home Server PP2 for several months with great success, but I just had a drive failure that shook my confidence in the whole system.

    I have duplication enabled on every shared folder, but when one of my drives failed I could no longer access a vast majority of the files in each folder.  Some were still accessible, however, and I was able to browse through the various directories just fine.  I just couldn't open/view/copy most of the files.  (These files happened to be all the photos and videos of our four month old, so my wife and I nearly suffered heart attacks.)

    In the network health screen, WHS showed file conflicts in each of my shared folders.  Before the drive failure there were no file conflicts and network health was nice and green.


    Shouldn't file duplication behave somewhat like RAID-1 when a drive fails and still let me open/copy/backup the secondary copy of the file?  If not, what did I gain by using file duplication?  I'd expect all sorts of network health warnings about the missing drive, but no interruption in access to my duplicated data.

    1. How are you attempting to access the files?
    2. What error are you receiving? Are the errors referring to files on the missing drive?
    3. Have you removed the missing HDD from your system using the Windows Home Server console? If you have not removed the drive via the console, you will need to do this.

    You can use the Windows Home Server Console to inform Windows Home Server Drive Extender that a missing hard drive will never be used. The Migrator service will enter a special repair mode, and it will inspect every tombstone file. If the tombstone had an alternate shadow on the missing hard drive, that link is removed from the reparse point on the tombstone. The Migrator service attempts to make an extra copy of the file later (so the file is duplicated again). If the master shadow was on the missing hard drive, the most recent alternate shadow is promoted to become the master shadow. If a file was not duplicated and the only shadow copy of the data was on the missing hard drive, that data is lost. The Migrator service still has work to do because a file with no remaining shadow files cannot be opened or deleted. If the Migrator service left the tombstone alone, it would continue to appear in the directory, and the user would have no easy method for deleting it. While in repair mode, when the Migrator service finds a tombstone file for which the only shadow was on a permanently missing hard drive, the Migrator service deletes the tombstone.

    Thanks!
    Lara Jones [MSFT] | Program Manager
    Community Support and Beta | Windows Home Server Team
    Windows Home Server Team Blog
    Connect Windows Home Server
    Windows Home Server
    Wednesday, June 10, 2009 7:32 PM
    Moderator
  • Lara,
    1. I attempted to access the files using robocopy and plain old windows explorer from an XP box and a Vista box.  In both cases, many files would not open although I could browse the shared folders' directory trees.

    2. I don't have it in front of me right now, but robocopy said something like the device is not ready and it couldn't read the file.

    3. I did not remove the hard drive from the console, but it was marked as missing.  Shouldn't WHS let me access the duplicate copy of the file in the event that one copy is on a missing drive?

    It seems awfully risky to remove the drive to restore access and have the Migrator potentially delete files that it can't find on the remaining drive for whatever reason.  In other words, all the file conflicts and the fact that I can't access any data doesn't give me great confidence that removing the drive from the console is going to do the right thing either.

    Is there no way for duplicated shared folders to simply fail over to one copy when the other copy's drive goes missing for whatever reason?  What if the second copy was on an external drive with a bad power supply?  I'd have to cross my fingers and completely remove the drive from WHS to access the files while I order a new power supply?

    Thanks,
    Josh
    Wednesday, June 10, 2009 9:03 PM

  • 1. I attempted to access the files using robocopy and plain old windows explorer from an XP box and a Vista box.  In both cases, many files would not open although I could browse the shared folders' directory trees.

    2. I don't have it in front of me right now, but robocopy said something like the device is not ready and it couldn't read the file.


    This is because it is trying to access the files that are on the missing drive.


    3. I did not remove the hard drive from the console, but it was marked as missing.  Shouldn't WHS let me access the duplicate copy of the file in the event that one copy is on a missing drive?

    It seems awfully risky to remove the drive to restore access and have the Migrator potentially delete files that it can't find on the remaining drive for whatever reason.  In other words, all the file conflicts and the fact that I can't access any data doesn't give me great confidence that removing the drive from the console is going to do the right thing either.


    If duplication was enabled and you remove the missing drives, the alternate shadows will be promoted. The deletion it is refering to are the tombstones that point to files that were in non-duplicated shares on a drive that has been removed i.e. there is only one shadow. Files that are duplicated have two shadows a master and an alternate (secondary).

    If the second copy was on a file with a bad power supply, the master shadow is unaffected and will create an alternate shadow on the next migration pass. Also, if you remove the missing drive with the bad power supply via the console and plug the HDD into another PC with the new power supply, the file is available under the \DE path providing that no corruption took place on the drive due to the bad power supply.

    If the HDD with a bad power supply is plugged back in once a new power supply is attached, then this entire situation is resolved once the server is rebooted.

    Please see the Drive Extender Technical Brief for more information.
    Lara Jones [MSFT] | Program Manager
    Community Support and Beta | Windows Home Server Team
    Windows Home Server Team Blog
    Connect Windows Home Server
    Windows Home Server
    Thursday, June 11, 2009 12:31 AM
    Moderator
  • Lara,
    1. I attempted to access the files using robocopy and plain old windows explorer from an XP box and a Vista box.  In both cases, many files would not open although I could browse the shared folders' directory trees.

    2. I don't have it in front of me right now, but robocopy said something like the device is not ready and it couldn't read the file.

    3. I did not remove the hard drive from the console, but it was marked as missing.  Shouldn't WHS let me access the duplicate copy of the file in the event that one copy is on a missing drive?

    That depends on which copy of the data is missing.  If your alternate (second) shadow is on the drive that failed, you should still be able to open the file.  If, however, the primary (first) shadow is on the drive that failed, the alternate shadow needs to be promoted to primary and that won't happen until you remove the failed drive from the server.  (That's also why you can open some, but not all, of the files.)

    It seems awfully risky to remove the drive to restore access and have the Migrator potentially delete files that it can't find on the remaining drive for whatever reason.  In other words, all the file conflicts and the fact that I can't access any data doesn't give me great confidence that removing the drive from the console is going to do the right thing either.

    That's how it's designed to work.  What makes you think it's not "going to do the right thing"?  (If you're that worried about it, you could always shut down your server, disconnect each working drive and copy all of the data from all of the drives to another location.)

    Is there no way for duplicated shared folders to simply fail over to one copy when the other copy's drive goes missing for whatever reason?

    That's not how it works.  However, you could always suggest that on Connect.

    What if the second copy was on an external drive with a bad power supply?  I'd have to cross my fingers and completely remove the drive from WHS to access the files while I order a new power supply?

    Thanks,
    Josh

    • Marked as answer by Josh Christie Thursday, June 11, 2009 8:44 PM
    Thursday, June 11, 2009 12:37 AM
    Moderator
  • Thanks for the answers to my questions.

    I'm still surprised that WHS won't fail over to the secondary copy of the files in the event of a drive going missing.  This seems to go against the idiot-proof (in a good way) design of WHS.  I certainly wouldn't want any non-technical family members removing drives from WHS and clicking through the "you may lose data" warning just to access shared folders if a drive failed when I wasn't home.

    If all folders are duplicated and a drive fails, I'd expect a single critical network health warning of "drive X is missing" instead of all sorts of file conflicts.  At that point, shared folders would fail over to the secondary copy and remain accessible.  If space were available, they would auto-replicate to other drives to restore the duplication.  If no space were available, they'd auto-replicate when a new drive is installed.

    I hope this is the direction Home Server is headed because despite this experience, WHS really is a killer product.  The auto-failover and re-duplication features would make it a hands-down winner over simple RAID-1 NAS.

    Thanks,
    Josh
    Thursday, June 11, 2009 8:44 PM