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Unable to perform System Backup in CBFS Drive

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#24484
Posted: 04/08/2013 20:03:20
by Kenny Kim (Standard support level)
Joined: 08/19/2009
Posts: 38

Good morning.

We are not able to backup Windows to CBFS Drive.

Drive parameters are as following:
Code
mCbFs.StorageType = CbFsStorageType.stDiskPnP;
mCbFs.StorageCharacteristics = 0;
mCbFs.DisableFileCache(true);
mCbFs.DisableMetaDataCache(true);
mCbFs.SerializeCallbacks = false;
mCbFs.UseFileCreationFlags = true;


Drive is created and mounted as following:
Code
mCbFs.CreateStorage();
mCbFs.MountMedia(0);
mCbFs.SetFileSystemName("NTFS");
mCbFs.AddMountingPoint(driveLetter + ":", CallbackFileSystem.CBFS_SYMLINK_MOUNT_MANAGER, null);


CBFS Version: 3.2.121.305
API: .NET 4.0
OS: Windows 7 Enterprise x64, Windows 7 Professional x64, Windows Server 2008 R2 x64

Windows Backup fails, indicating that backup did not complete successfully.
There are no errors thrown in CBFS side.

But, if we share some folder located in CBFS Drive and save the backup there, backup completes successfully.

We have reproduced the issue with same behaviours with Mapper Sample (.Net ver.). We have changed some parameters to match our drive's parameters:

Code
private void btnCreateStorage_Click(object sender, EventArgs e)
        {
            try
            {
                ...
                mCbFs.StorageType = CbFsStorageType.stDiskPnP;
                mCbFs.StorageCharacteristics = 0;
                mCbFs.CreateStorage();
                ...
            }
        }


Code
private void btnMount_Click(object sender, EventArgs e)
        {
           ...
            try
            {
                mCbFs.MountMedia(0);
                mCbFs.SetFileSystemName("NTFS");
                mCbFs.AddMountingPoint(edtMountinPoint.Text, CallbackFileSystem.CBFS_SYMLINK_MOUNT_MANAGER, null);
             }
           ...            

        }




Thank you.
#24486
Posted: 04/09/2013 01:16:16
by Volodymyr Zinin (EldoS Corp.)

Hello Ulughbek,

Perhaps the problem is because you named the file system as "NTFS" and Windows sends some NTFS specific request which CallbackFS doesn't handle. Could you please run Process Monitor from sysinternals.com, set there to filter only operations for your virtual disk (by setting the filter "Path"->"begins with"->"X:", where "X:" is your drive letter), reproduce the problem, save the log in the Process Monitor native format (which is .pml), and give it to me.
Thanks.
#24487
Posted: 04/09/2013 01:18:04
by Eugene Mayevski (EldoS Corp.)

But the optimal approach is not to set the filesystem to NTFS - there are *many* requests specific to NTFS that CBFS doesn't support now and while we will implement handling of some requests in future, other requests are not documented and thus can not be implemented.


Sincerely yours
Eugene Mayevski
#24492
Posted: 04/09/2013 04:12:42
by Kenny Kim (Standard support level)
Joined: 08/19/2009
Posts: 38

Sending Mapper's log file.

Quote
But the optimal approach is not to set the filesystem to NTFS

Unfortunately, Windows Backup Application cannot save System Image on Fat32 file system (4GB size limit?).

Thank you.


#24493
Posted: 04/09/2013 04:28:12
by Volodymyr Zinin (EldoS Corp.)

Quote
Ulughbek Muslimov wrote:
Sending Mapper's log file.

Where is it? I don't see it :)
#24494
Posted: 04/09/2013 04:40:46
by Kenny Kim (Standard support level)
Joined: 08/19/2009
Posts: 38

Sorry.
I've attached it as a JPG.
Logfile.rar.JPG (URL: https://www.eldos.com/bitrix/components/bitrix/forum.interface/show_file.php?fid=15825)

BTW, you can reproduce the problem using Mapper sample by editing a few lines in btnCreateStorage_Click() and btnMount_Click() events as shown in my first message. The rest of the code is not changed at all.

Thank you.
#24498
Posted: 04/09/2013 05:41:06
by Volodymyr Zinin (EldoS Corp.)

Most probably the problem is because vssvc.exe (Volume Shadow Copy Service) sends the undocumented requests FSCTL_QUERY_DEPENDENT_VOLUME and IOCTL_STORAGE_QUERY_DEPENDENT_DISK. But CallbackFS doesn't handles them and competes with the "invalid device request" error.
These are the last requests that are sent to the virtual disk.
Also by EldoS: RawDisk
Access locked and protected files in Windows, read and write disks and partitions and more.

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