Disk-to-Disk Backup Questions

[Doug_Dockter]

I'm starting to experiment with disk-to-disk backups. I plan on doing differential backups to disk Mon - Thurs and a full backup on Friday. I'll do a copy-to-tape after each backup. Is there an advantage one way or the other to creating a new backup set for each of the Mon-Thurs backups or just creating one Monday and appending to it? Would fragmentation be worse one way or the other?

I tried implementing Hotfix 27 (preallocation), but got a gazillion of the following errors in my Application log and the job just hung.

An error occurred while processing a B2D command.
Drive: WriteMasterFMTable() SetFilePointer failed (G:\@@@@@@@@.bkf). Error=6

[padmaja_rajopad]

Hi,

Try deleting the Backup to Disk folder from Backup Exec.Recreate the folder in another path and check whether the job still hangs.


Regards
Padmaja

[Doug_Dockter]

I did some experimenting and it appears that the max preallocation that is supported is 99GB. If I preallocate 99GB and below, the job runs fine. 100GB and above the job hangs.

[priya_khire]

Hello,

Are you talking about the disk space reserve option? You could select the option of appending to the disk everyday or creating separate sets. Did hotfix 27 help?

[Doug_Dockter]

I'm talking about the "maximum size for Backup-to-disk files" option. I'm not sure if HF 27 is helping or not. I have the above option set to 20GB. My backup job is set to Append. I completely defragged my drive (1.8TB) and have since run two nights of backups to it. I did an Analyze on the drive, and following are the stats:

Volume Fragmentation
Total Fragmentation = 33%
File Fragmentation = 67%
File Fragmentation
Total Files = 26
Average File Size = 14,628MB
Total Fragmented Files = 10
Total Excess Fragments = 36,355
Avg Fragments Per File = 1,399

I have the registry key HKLM\Software\Veritas\Adamm\B2D\PreAllocate set to 1 so that should enable HF27.

[padmaja_rajopad]

Hi,

The Backup to Disk folder should have the "B2Dxxxx" files in it and not the@@@@@@ file which you are seeing?

Did you recreate the Backup to Disk folder?

Regards
Padmaja

[Doug_Dockter]

Yes I did recreate the B2D folder. I can reproduce this problem whenever I set the the "maximum size for Backup-to-disk files" option to something greater than 99GB. It then puts the @@@@@@ entry in the B2D folder and the job just hangs. If I set the "maximum size for Backup-to-disk files" option to something less than 100GB it works OK. I was trying to use a larger number for my full backup because I thought it might help reduce fragmentation.

[Gauri_Ketkar]

Hi,

Test 1 > create a B2D on any remote server and set this option "maximum size for Backup-to-disk files" to greater than 99GB.

Test 2 > create a B2D on another HDD drive locally and try backups




Update us on the same and revert for any further Query



Thank you
Gauri