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NTbackup and C1557A

Charlie Jolly
Occasional Visitor

NTbackup and C1557A

Hi - I appreciate anyone who can help.

Question 1
Hoping someone can shed some light on my problem.

I keep getting the following message (see bottom of message) during backup. I have previously not had a problem. I have tried different tape sets. I have tried new tapes. I have tried new cleaner. I have ran TapeTools and both the drive and autoloader pass. The drive passes with warnings which indicate that the drive has not been cleaned enough. However I have cleaned the drive five times in a row more than once.

The only problems that I have had in the last year with the tape drive is that the cleaning cartridge kept getting stuck recently and I had to put an empty mag into the drive to retrieve the tape then NTbackup/Remote storage threw a wobbly when I tried to change the cleaning cartridge after it reached 0 cleans left.
I had to delete the library before I could get the drive working again.

Since then I have had the problem. There are no error messages in Event log apart from bad block messages when the drive is cleaned which I believe is normal.

Is it possible that it is a timeout issue? The drive is set to 5 mins under Computer Management > Removable Storage > Drive > Properties.

Error message in backup log file. This was after approx 10 hours and on the third tape. The removable storage queue last indicated a MOUNT operation. I believe that maybe NTBACKUP is failing to send a DISMOUNT before it changes tape again to verify.

Backup completed on 29/04/2003 at 00:44.
Directories: 27496
Files: 138317
Skipped: 11
Bytes: 31,099,556,161
Time: 9 hours, 57 minutes, and 3 seconds

Error: The device reported an error on a request to mount the media.
Error reported: Unknown error.


Verify Status
Operation: Verify After Backup
Active backup destination: 4mm DDS

Error: The device reported an error on a request to mount the media.
Error reported: Unknown error.

Question 2
Should I bother with a verify when using the HP tapes as I have read that this puts undue strain on the drive?

Question 3
Should I install the HP driver as opposed to 4mmdat.sys? I have read that they are the same.


Arimo Laine_2
Valued Contributor

Re: NTbackup and C1557A



Your backup is unacceptably slow. The data transfer is ~31100 MB in 597 min, which makes ~ 52MB/min i.e. less than 1MB/second. A Dat24 drive needs a minimum of 1MB/s to work, preferably the data stream should be >2MB/s which is the drive transfer rate with HW compression on. This kind of data stream will eventually kill the drive.

The drive is designed to work for less than 5 hours / day, so you're stressing its capabilities almost twofold.

I would think that you have hard drive and the tape drive installed on the same SCSI bus. This is not a good idea, as it leads frequently to data stream problems. So, put the drive to a dedicated controller (or at least to a dedicated SCSI bus) with a terminated cable.

Make sure that your SCSI controller driver is correct and current, do not use Microsoft driver unless the manufacturer expressly recommends that.


Regardless of the tape manufacturer, verify is not necessary with a Dat24 drive, as it does read after write by default anyway.


Yes you should.

Eugeny Brychkov
Honored Contributor

Re: NTbackup and C1557A

Arimo is absolutely correct. Drive should be cleaned after every 5 full backups or 20 tape pulling hours. Please generate support ticket for autoloader (not only for drive) and attach to your next reply zipped
Charlie Jolly
Occasional Visitor

Re: NTbackup and C1557A


Thanks for responses.

Last night I ran a backup and turned verify off! The job completed. It seems that maybe NTbackup is the problem here, where it was trying to mount a tape before the original had been dismounted. Also I have changed 4mmdat.sys to the latest hpdat.sys as recommended. Also I will not verify backups if it is unnecessary. (I fear paranoia might set in now though!)

I have attached the job ticket in a zip file as regards to cleaning log. Ntbackup automatically cleans between tape changes. Is this a drive request or is it part of Ntbackup? I have always cleaned the drive when changing the magazines between backups. Maybe I have a duff cleaning tape - I'll change that too.

As for the transfer rate I am concerned that the server is slower than expected. The tape is running on its own SCSI controller. Although this is the supplied MS driver.

I am a believer in not updating drivers when things work. However if the transfer rate is too small then should I update the SCSI driver as well?

Config of TAPE SCSI
Adpatec AIC-7899 Ultra160/m PCI SCSI Card > adpu160m.sys (MS Driver)
4mmDAT Medium Changer > DDSMC.sys (MS Driver)
HP C1557A SCSI Sequential Device > 4mmDAT.sys (MS Driver)*

*Changed 4mmDAT to latest HPDAT now

Backup log file.

Backup Status
Operation: Backup
Active backup destination: 4mm DDS
Media name: "Media created 29/04/2003 at 16:12"

Backup of "H: Raid 2"
Backup set #1 on media #1
Backup description: "Set created 29/04/2003 at 16:12"
Backup Type: Normal

Backup started on 29/04/2003 at 16:58.
Backup completed on 30/04/2003 at 02:29.
Directories: 2410
Files: 25147
Bytes: 33,468,905,197
Time: 9 hours, 7 minutes, and 52 seconds




Is there an updated driver for the changer.
DDSMC.sys (MS Driver)
Charlie Jolly
Occasional Visitor

Re: NTbackup and C1557A


Job Ticket
Charlie Jolly
Occasional Visitor

Re: NTbackup and C1557A

In reply to the data rate killing the drive.

There are two RAIDS on a seperate SCSI card. In addition there is a File Replication Service running on the data being backed up. The full backup is done weekly so 9hrs a day is not typical. Normally the weekly takes approx 12 hrs with differentials taking up a further 4hr a week. This makes 16hrs a week. (Although this was doubled when I had Verify turned on.)

If the 24x6 is not suitable then can someone suggest an alternative solution.

I have two RAID5s that need backing up. Both RAIDs have a capacity of 100GB. This is maximum capacity. Working shares account for approximately 30GB on each RAID. This gives approximately 60GB data to backup weekly.