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12.5 Disk to Disk Backup

soulestream
Level 2
I just changed jobs and the company uses BE 12.5.

The previous backup scheme was horrible and I am trying to hammer my way through setting up a good B2D backup.

I need some clarification on the best way to set some of these options.

Maximum number of backup sets per backup-to-disk file. This was previously set to 100, I have moved it back to 10 as my understanding from BP is this will help speed up the rotation of media.

Maximum size for backup-to-disk files. This is currently set to 4GB. Is there any reason I shouldn't make this larger?

Allocate the maximum size when creating the backup-to-disk file. Was checked.
Best Practices says this will/could slow down the backup job.

Per my understanding this just means if the option above it is set to 2GB, then it makes all the files 2GB regardless of what the size of the backup set is. Is that correct?

I have adjusted most of the options based on feedback on the forums and BP, but the B2D settings are confusing me a bit and I want to make sure I am gettign the best performance out of the backup. My concern is my B2D backups are taking a lot longer than my tape backups.

Exchange backup to tape (LTO2-U160) 1 hour
Exchange backup to disk (ISCSI SAN) 8 Hours

Lastly, I had several Scrath Media disks created that all show they are 2K in size. They are actually 4GB on disk. Is this normal? I am assuming it was recycled media, but I am not sure why it shows 2K.

Thanks






1 REPLY 1

Ken_Putnam
Level 6
Maximum number of backup sets per backup-to-disk file. This was previously set to 100, I have moved it back to 10 as my understanding from BP is this will help speed up the rotation of media

This controls the number of different resources that can exist in one BKF file.  if you set it to 1, then each share, database, system state, etc will open a new BKF regardless of how mucj space is unused in it

Maximum size for backup-to-disk files. This is currently set to 4GB. Is there any reason I shouldn't make this larger?

if you set this way up, you can wind up with lot of wasted space at the end of the last BKF file of each backup job.  Should be used with number of sets per BKF

Allocate the maximum size when creating the backup-to-disk file. Was checked.
Best Practices says this will/could slow down the backup job.

Per my understanding this just means if the option above it is set to 2GB, then it makes all the files 2GB regardless of what the size of the backup set is. Is that correct?


This will indeed make the job that creates the BKF file run longer, but can greatly reduce fragmentation on the B2D device.  Fragmentation can absolutely kill through-put.  When the file is reused, since it is alread allocated, there will be no difference  As far as all files at the set size, this would only affect the last BKF file of a job (see above about wasted space)

As for your last two questions

How fragmented is the iSCSI device. Is it the only device on the SCSI channel?

Not sure about the file size question.  If you write data to the BKF files, do they stil show up as 2K?