NTbackup and C1557A

[Charlie Jolly]

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.

Thanks

Charlie

[Arimo Laine_2]

Hi.

Q1:

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.

Q2:

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

Q3:

Yes you should.

HTH,
Arimo

[Eugeny Brychkov]

Charlie,
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
http://h18006.www1.hp.com/products/storageworks/ltt/index.html
Eugeny

[Charlie Jolly]

HI

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

----------------------

Thanks

Charlie

p.s
Is there an updated driver for the changer.
DDSMC.sys (MS Driver)

[Charlie Jolly]

Ooooops

Job Ticket

[Charlie Jolly]

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.

Cheers

Charlie