TIR With Move Detection Time Question 2

[ElPatNot]

We are currently in a production enviroment and trying to plan to make some dramatic changes to our architecture. For example, we are going to start using inline tape copy, and we are using the assumption that it will add approximately 30% to the backup times for full backups (20 minutes for every hour).

My question is, if we start using True Image Restore (TIR) and enable Move Detection, does anyone know if there is a similar percentage that we can use to plan this? Or is it server/data dependant? Is there any kind of high-end/low-end precentages that we can use to estimate the backup times for full backups? Or is this just a "change-it-and-see-what-happens" situation? Thanks in advance!

Patrick

 

[DRFranco]

I don't know if this is much help but we use in-line tape copy and it seems to work fine. We like the fact that the backup continues even if one copy fails. I don't know what your environment is but if you are using any flavor of UNIX then you really need to use TIR. If you do not use TIR w/ move detection then the increnmentals will not pick up any new files added to the file system since the last backup. See below from support's email to me...

In a nutshell, this is exactly what non-TIR backups do. Technically speaking, non-TIR backups will only find files that already existed during the full backup that have had their mtime (modified time) inode property updated to a more recent timestamp. In other words, non-TIR backups only pick up file modifications. Here's a list of the types of file modifications that are picked up by TIR but not non-TIR backups (for a complete list of the functions or lack thereof of these types of backups please refer to the NetBackup System Administrator's Guide for Unix for further information in our official documentation):

http://support.veritas.com/docs/268090

(Vol I)

http://support.veritas.com/docs/268091

(Vol II)

non-TIR incremental backups have the following drawbacks (for example; this is not a complete list; that's in the Guide)

- It won't back up newly created files
- It won't backup up files that have been mv'd to another location
- It won't properly recognize directories have moved
- It won't acknowledge the fact that files have been removed and will end up being restored even it they were removed prior to the incremental backup image you're selecting
- Restores may not honor directory permissions 100% of the time

TIR backups' drawbacks involve the amount of resources it takes up as the backup is in progress (the problem in importing TIR features into non-TIR backups is the overhead considerations). However, the way to restore the functionality you're looking for is to use the NetBackup feature designed to recognize newly created files: TIR backups.

 

[ElPatNot]

That's great!! Thanks for your answer!!

But I was just wondering about a percentage of resources that would be added if you switch TIR on.

For example, if Job 1 takes an hour, and with TIR on and Move detection, Job 1 now takes 1.5 hours. That's what I'm looking for. And if this is a RTFM answer, just nudge me in near the correct direction and I'll go.

Patrick

 

[comtec17]

TIR will not increase any backup times.