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Issues with a Duplicate (operation) Script


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I, allegedly, hijacked a thread and posted this:

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Hello. I am using Retrospect v6.1.126 with Mac OS X Server v10.4.4. I have a duplicate script that is configured to select all files and replace entire contents of the destination drive. I am using this as a means of backing up a large (94GB) drive to a second drive in the event of a failure.

 

That failure occurred today, so I was prepared. However, a few users are reporting that their folders don't contain files from several months ago. Does anyone have an idea why this would be the case? Why would a file or folder from the source disk not be duplicated to the destination disk if all files are to be selected and replace entire contents is engaged?

 

To tie this in with ACLs, does Retrospect preserve ACLs during a duplication operation? I had to reconfigure my ACLs on my backup (now primary) drive. Would there have been an easier way to restore my ACLs?

 

Thanks for reading!

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So then rhwalker claims that was a hijacking of a thread. That's debatable. Regardless, he was kind enough to respond with this:

 

(1) You should start a new thread rather than to hijack this old, dead thread - this is not related to the previous poster's problem.

 

(2) duplicate is not a backup; it's a duplicate of that instant. If the files weren't there at the time of the last duplicate, then they won't be there now. Sounds to me like you should be using backup, not duplicate.

 

(3) have you checked your selectors? Is it possible that the selectors caused some files to be excluded? Yes, I understand from your post that your script is configured to "select all files", but is there perhaps a selector involved?

 

(4) Retrospect will not be able to back up or duplicate files that are open; that's the way unix works. Is it possible that the files were open by some application at the time of the duplicate?

 

Russ

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To which I respond:

 

(2) Unless I am misunderstanding the Retrospect documentation, I can't have Retrospect backup files to another volume and be able to use that volume on a whim like I can with a duplicate. If I'm wrong about this, please tell me what chapter to re-read in the documenation. I need to be able to say "Darn, this disk died, let me grab the duplicate and get back to work" (which is exactly what I did earlier today).

 

If the files were on the source volume the last time the duplicate operation ran (at midnight), why are they not on the destination volume now? No, I didn't delete them.

 

(3) No additional selectors were specified for this script.

 

(4) Is it possible? Anything is possible. Is it likely? No.

 

Now, the other issue I posted about with regards to the duplicate option was this. Are ACLs on the source volume preserved on the target volume during a duplicate operation? Either I did something wrong, or this is not the case. I am interested in having this suspicion confirmed.

 

Thanks for reading!

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>If the files were on the source volume the last time the duplicate operation ran (at midnight), why are they not on the destination volume now?

 

Files present on the Source will be present on the Destination after a Duplicate.

 

>a few users are reporting that their folders don't contain files from several months ago.

 

"several months ago" suggests the possibility that the files were not, in fact, present on the Source at the time the Duplicate ran.

 

Retrospect does not treat older files differently from newer files for the purposes of matching. The fact that only "old" files are missing suggests that the user(s) discarded them at some point before your Duplicate operation ran.

 

>Unless I am misunderstanding the Retrospect documentation, I can't have Retrospect backup files to another volume and be able to use that volume on a whim like I can with a duplicate

 

This is correct.

 

Backup and Duplicate are both valuable data management tools. The former allows for recovery of deleted or corrupted files over time, while the latter provides the fastest road to disaster recovery. Which you use, or how you use them both, depends on your needs. Einstein proved that time is money. As a backup administrator it's your job to decide how to allocate both.

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Quote:

(2) Unless I am misunderstanding the Retrospect documentation, I can't have Retrospect backup files to another volume and be able to use that volume on a whim like I can with a duplicate. If I'm wrong about this, please tell me what chapter to re-read in the documenation. I need to be able to say "Darn, this disk died, let me grab the duplicate and get back to work" (which is exactly what I did earlier today).

 


You are correct. A duplicate makes file system copies that allow you to move files around. A backup lets you restore (using the Retrospect restore operation) from a snapshot at any point during the history of that backup set. There are no snapshots with duplicate; it's just file copies.

 

Personally, I would (and do) use a RAID 1 mirror and RAID 5 to do what you are doing, and use Retrospect to backup our network and server to tape in case of inadvertent file deletion, but that's simply a matter of personal choice because of our backup policy requirements, which seem to be different from yours.

 

There is no way for Retrospect to preserve ACLs unless the duplicate destination has ACLs turned on. Here are the release notes for Retrospect 6.1, which added support for ACLs:

Retrospect 6.1 release notes

 

The release notes indicate that Retrospect supports ACLs for backup, duplicate, and restore, discusses the options, and discusses an Apple bug (regarding modification dates) for copying of files with ACLs.

 

Before deployment of Retrospect 6.1, I tested ACLs for backup and restore. I haven't tested ACLs for duplicate, so sorry, I can't answer your question on that.

Quote:

Now, the other issue I posted about with regards to the duplicate option was this. Are ACLs on the source volume preserved on the target volume during a duplicate operation?

 


The release notes indicate that they are if you have the appropriate option set in Options>More Choices>File Copying. Again, I haven't tested. But it would seem to be a requirement that the duplicate's destination volume had ACLs turned on. Were they?

 

Regards,

 

Russ

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Personally, I would (and do) use a RAID 1 mirror and RAID 5 to do what you are doing, and use Retrospect to backup our network and server to tape in case of inadvertent file deletion, but that's simply a matter of personal choice because of our backup policy requirements, which seem to be different from yours.

 


Are you using 3rd party software or hardware for your RAID? I don't believe Disk Utility will let you create a RAID 5. It lets you create a RAID 1 (mirror) and some other level (striped). It does not let you do both, and it does not let you have more than one RAID of any type on a SCSI channel.

 

Thanks for the release notes link. It says ACL preservation is on by default, so I must not have had the other drive enabled for ACLs.

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Are you using 3rd party software or hardware for your RAID?

 


yes.

The RAID 5 is via the Apple Hardware RAID card in our Xserve G5, across 3 x 250 GB ADMs in the Xserve.

The RAID 1 mirror is via SoftRAID.

 

The reason we use SoftRAID is that a RAID 1 mirror split is the only way I know to clone a running server in an instant without taking it down, and even then it has to be done carefully so that databases are consistent at the instant of split (add a drive to the mirror, allow mirror to rebuild, turn off mail service, split the mirror to get a clone, turn on mail service). We have one RAID 5 LUN on the Apple Hardware RAID for our OS volume and one RAID 5 LUN for our user data. We do the mirror split dance prior to every software update on the Xserve so that we could fall back if the update goes badly.

 

SoftRAID is a very nice product, reasonably priced, very reliable, and their support is excellent. But all we use it for is mirror splits. We depend on Retrospect for our backups to our Exabyte VXA-2 1x10 1U PacketLoader (SCSI).

 

Regards,

 

Russ

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