How ntbackup software backup sparse file.

NTFSD
1

If I have 1GB file, it’s sparse and has been set 0 by FSCTL_SET_ZERO_DATA
for the whole range. Will ntbackup backup the 1G or smart enough only
backup what’s needed

Thanks.

2

If the file is read using ReadFile, a whole gig of 0 set bytes will be
returned. But if you use BackupRead, only the actually amount of
data in the data stream will be returned. If you use BackupRead/backupWrite
no additional steps are needed to handle sparse files correctly.

-----Original Message-----
From: xxxxx@math.uic.edu [mailto:xxxxx@math.uic.edu]
Sent: Wednesday, May 15, 2002 12:45 AM
To: File Systems Developers
Subject: [ntfsd] How ntbackup software backup sparse file.

If I have 1GB file, it’s sparse and has been set 0 by FSCTL_SET_ZERO_DATA
for the whole range. Will ntbackup backup the 1G or smart enough only
backup what’s needed

Thanks.

You are currently subscribed to ntfsd as: xxxxx@commvault.com
To unsubscribe send a blank email to %%email.unsub%%

3

NtBackup shipped with Win2K & above is sparse file-aware & backs
up/restores only allocated ranges.
Ravi

This posting is provided “AS IS” with no warranties, and confers no
rights.

-----Original Message-----
From: Jeremy Schwartz [mailto:xxxxx@commvault.com]
Sent: Wednesday, May 15, 2002 7:45 AM
To: File Systems Developers
Subject: [ntfsd] RE: How ntbackup software backup sparse file.

If the file is read using ReadFile, a whole gig of 0 set bytes will be
returned. But if you use BackupRead, only the actually amount of data in
the data stream will be returned. If you use BackupRead/backupWrite no
additional steps are needed to handle sparse files correctly.

-----Original Message-----
From: xxxxx@math.uic.edu [mailto:xxxxx@math.uic.edu]
Sent: Wednesday, May 15, 2002 12:45 AM
To: File Systems Developers
Subject: [ntfsd] How ntbackup software backup sparse file.

If I have 1GB file, it’s sparse and has been set 0 by
FSCTL_SET_ZERO_DATA for the whole range. Will ntbackup backup the 1G or
smart enough only backup what’s needed

Thanks.

You are currently subscribed to ntfsd as: xxxxx@commvault.com To
unsubscribe send a blank email to %%email.unsub%%

You are currently subscribed to ntfsd as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to %%email.unsub%%