NTBackup - Error writing to media - Output to compressed file on disk - 32GB limit?

[Ken Levy]

We are using NTBackup to create backups of user and server hard drives onto
large (>200 GB), inexpensive IDE hard drives in removable drive carriers.
This procedure has worked very well for us with one exception.

To optimize the space on the backup hard drive, we set up the target
directory (which receives the *.bkf file for the backup files) as
compressed.

We have one shared server hard drive that has over 50 GB of data on it.
When we run NTBackup (Win2000 Professional with all the latest Windows
Updates applied) on this drive, we get the following messages:

Error: The device reported an error on a request to write data to media.
Error reported: Unknown error.

These errors appear after the backup has been running 4 hours + and has
backed up 45,764,258,290 bytes. After further investigation, we found that
the backup file (*.bkf) created by the routine showed the following
filesizes (as reported by Windows Explorer):

Size: 42.6 GB (45,812,942,848 bytes)
Size on disk: 30.4 GB (32,688,783,360 bytes) (Note: target directory is
compressed)

My questions are as follows:

1) Is there a maximum compressed file size of 32GB on the media? I wasn't
able to find anything in the KB documenting such a restriction?

2) Is this a bug or documented restriction in NTBackup?

Given the falling prices, increasing capacities, removeability (via USB2.0
or IEE1394) and higher speed / reliability of IDE hard drives (versus tape),
I think we will be seeing more and more people switching over to disk based
backup media from tape, and resolving this issue will be important.

TIA for any comments, fixes, etc.

Please post any responses to the newsgroup.

 

[kinveachy]

Ken,

We are having a very similar problem to yours.

We have a central STORAGE server which is nothing more than an IDE
server with lots and lots of disk space. Every night, several of our
servers on the network run NTBACKUP and copy across .bkf files to our
STORAGE server. These .bkf's range from 500mb to 32GB's in size.

Some nights all jobs go through fine, however, usually half of the jobs
fail due to:

Error: The device reported an error on a request to write data to
media.
Error reported: Write protected media

There doesn't seem to be any pattern with which jobs fail and which
one's don't and this jobs are sometimes near completion 28gb's of
32gb's...

Since we seem to be having a fairly similar problem, i was wondering
whether you may have had any luck solving this issue?? It's driving me
mad and all the research i've done points this problem to be something
to do with backing up to DLT tapes - which i'm not doing!!

Have you managed to solve this?

Thanks,

Andy

 

[Ken Levy]

Andy:

No we haven't found a solution, other than to segment down the backups and
keep them less than
32 gb in size.

We ARE using a secondary IDE controller (a "Promise Technology Ultra100 TX2
which includes BIOS support for drives > 137 GB). I don't know if that may
be part of the root cause.

We have seen corruption of large partitions (>32gb) using this controller in
the NT4.0 environment. Our problem with NTBackup only seems to happen to
individual files in the Win2000 Professional environment used by our backup
system.

Are you using a secondary IDE controller, as well?

Ken