OSR's ntfsd List: Getting a volume GUID

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06 Aug 05 10:22

ntfsd member 18044

xxxxxx@acm.org

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Getting a volume GUID

HI all, I need to retrieve a volume GUID, i.e. the unique identifier of a partition like \??\Volume{GUID}\ I have either the NTFS device name or the DOS device name (\DosDevices\c:). At the moment I use a IOCTL_MOUNTMGR_QUERY_POINTS where I put the device name (both NTFS and DOS) in the MOUNTMGR_MOUNT_POINT parameters DeviceNameOffset and DeviceNameLength. Then I filter the answer and save the first symbolic link that starts with \??\Volume{. 1) Is there an easier way to get the Volume GUID? 2) Can I use IOCTL_MOUNTDEV_QUERY_UNIQUE_ID? I guess the ID I get is different from Volume GUID. Is it really unique? 3) Can I use a DOS device name as device name parameter in MOUNTMGR_MOUNT_POINT? It works on Windows XP, what about other Windows? Thank you Francesco

Message 2 of 5

06 Aug 05 14:47

ntfsd member 25865

xxxxxx@emc.com

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Getting a volume GUID

>2) Can I use IOCTL_MOUNTDEV_QUERY_UNIQUE_ID? I guess the ID I get is >different from Volume GUID. Is it really unique? - Yes, unique id is different than the volume GUID. Unique id is given by the volume manager controlling the volume. For Basic Volumes, its disk signature + offset and for LDM/VXVM volumes its volume GUID > >3) Can I use a DOS device name as device name parameter in >MOUNTMGR_MOUNT_POINT? It works on Windows XP, what about other Windows? - I think it works on WINDOWS 2000 platform onward. >-----Original Message----- >From: Francesco Garelli [mailto:xxxxx@acm.org] >Sent: Saturday, August 06, 2005 7:22 AM >To: Windows File Systems Devs Interest List >Subject: [ntfsd] Getting a volume GUID > >HI all, > >I need to retrieve a volume GUID, i.e. the unique identifier of a <...excess quoted lines suppressed...> --

Message 3 of 5

06 Aug 05 22:40

ntfsd member 18044

xxxxxx@acm.org

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Getting a volume GUID

Pashupati Kumar <xxxxx@emc.com> wrote in news:63712@ntfsd: >>2) Can I use IOCTL_MOUNTDEV_QUERY_UNIQUE_ID? I guess the ID I get is >>different from Volume GUID. Is it really unique? > > - Yes, unique id is different than the volume GUID. Unique id is given > by the volume manager controlling the volume. For Basic Volumes, its > disk signature + offset and for LDM/VXVM volumes its volume GUID Do you mean the disk hardware signature? Can I use the Unique id as an universal identifier even better than the volume GUID? Thanks Francesco

Message 4 of 5

06 Aug 05 23:46

ntfsd member 25865

xxxxxx@emc.com

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Getting a volume GUID

>Do you mean the disk hardware signature? Can I use the Unique id as an >universal identifier even better than the volume GUID? Disk Signature given by the Disk Class driver, 4-Byte number. This is not guranteed to be unique across host. [ This has changed with GPT disks]. Do you mean WWPN/WWNN as disk hardware signature? I think Volume GUID is still a better option. But somewhere, I read you can have multiple volume GUID for the same volume. I have never seen an example of this. >-----Original Message----- >From: Francesco [mailto:xxxxx@acm.org] >Sent: Saturday, August 06, 2005 7:40 PM >To: Windows File Systems Devs Interest List >Subject: RE:[ntfsd] Getting a volume GUID > >Pashupati Kumar <xxxxx@emc.com> wrote in news:63712@ntfsd: > >>>2) Can I use IOCTL_MOUNTDEV_QUERY_UNIQUE_ID? I guess the ID I get is <...excess quoted lines suppressed...> --

Message 5 of 5

07 Aug 05 00:43

Maxim S. Shatskih

xxxxxx@shadowstor.com

Join Date: 23 Feb 2000

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Getting a volume GUID

> Do you mean the disk hardware signature? No, the MBR partition table one. >Can I use the Unique id as an > universal identifier even better than the volume GUID? For many purposes - yes. Maxim Shatskih, Windows DDK MVP StorageCraft Corporation xxxxx@storagecraft.com http://www.storagecraft.com

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