WellingtonIS
asked on
Size vs Size on Disk
I have a corrupt drive according to windows. This is a san and there nothing wrong with the drive. This is a darn windows issue. Nevertheless, I have the information backed up on a NAS and because this information is vital, I'm checking the sizes of each folder just to be sure. I'm a bit confused because on the live drive I'm getting the following information:
example:
Live Drive Back up San
2004 size 435/size on disk 449 size 435/size on disk 438
2005 size 500/size on disk 510 size 500/size on disk 502
2006 size 527/size on disk 539 size 527/size on did 529
I've already lost 3 days of this vital data due to disk corruption and I don't want that to happen again. Am I ok?
example:
Live Drive Back up San
2004 size 435/size on disk 449 size 435/size on disk 438
2005 size 500/size on disk 510 size 500/size on disk 502
2006 size 527/size on disk 539 size 527/size on did 529
I've already lost 3 days of this vital data due to disk corruption and I don't want that to happen again. Am I ok?
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
Thanks at least I' m safe
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
"This is the size that remains unused in the last cluster allocated for the file." should of course have been "The difference is the size that remains unused in the last cluster allocated for the file." You may have noticed that the "size on disk" is always larger than the actual size.
Does the content compare equal?.... sizes say nothing about content of files.
The file might have been allocated and still be full of zero's because data wasn't written to it...
The file might have been allocated and still be full of zero's because data wasn't written to it...
If you need to be absolutely sure, you can run a hash comparison (the download below contains just a stand-alone exe that can just be copied to wherever you need it).
First create a checksum file for the "live" folder (maybe try it with a smaller test folder first to get a feel for it).
-add creates/adds a checksum database
-r is Recurse.
-bp sets the BasePath, which will be removed when storing the hash (required because you want to compare two different folders).
-xml sets the file where the hashes will be stored. Note: when this file exists (for example from a previous run against a different folder), the entries will be added to the existing ones, it will not be overwritten!
Now verify against the backup.
-v is Verify
The first folder must be the one in backup that matches the one where the respective files from the first run are stored.
-bp sets the BasePath again, must be the same as the first folder in this command.
-xml sets the file with the hashes from the first run
> redirects the output to the file specified
Availability and description of the File Checksum Integrity Verifier utility
https://support.microsoft.com/en-us/help/841290/availability-and-description-of-the-file-checksum-integrity-verifier-u
First create a checksum file for the "live" folder (maybe try it with a smaller test folder first to get a feel for it).
-add creates/adds a checksum database
-r is Recurse.
-bp sets the BasePath, which will be removed when storing the hash (required because you want to compare two different folders).
-xml sets the file where the hashes will be stored. Note: when this file exists (for example from a previous run against a different folder), the entries will be added to the existing ones, it will not be overwritten!
fciv.exe -add D:\Live\Data -r -bp D:\Live\Data -xml C:\Temp\fciv.xmlNow verify against the backup.
-v is Verify
The first folder must be the one in backup that matches the one where the respective files from the first run are stored.
-bp sets the BasePath again, must be the same as the first folder in this command.
-xml sets the file with the hashes from the first run
> redirects the output to the file specified
fciv.exe -v E:\Backup\Data -r -bp E:\Backup\Data -xml C:\Temp\fciv.xml >C:\Temp\fciv_results.txtAvailability and description of the File Checksum Integrity Verifier utility
https://support.microsoft.com/en-us/help/841290/availability-and-description-of-the-file-checksum-integrity-verifier-u
ASKER