Normal + Incremental Strategy?

[Jumpmail]

Hi there,

 

I really like the idea of rotating backup sets per week and keeping the last week of the month offsite. I would like to have each Monday be a Full (or Normal) backup, and then have Tuesday - Friday be an incremental so that should a user accidentally delete a file on Wednesday, and not tell me until Thursday, I can get the file from Tuesday's backup (if it were updated on Tuesday, otherwise Monday's backup).

 

What is the way to do this?

 

I am confused about how I can get multiple images to appear on the same backup set?

 

I am currently using only one script which is scheduled to do a Normal Backup Monday through Friday. I was hoping that I would be able to restore files backed up from each previous day, but it doesn't appear so, when I go to do a restore all I see is the last night's backup image.

 

 

Thanks for any help,

 

 

Shaun

[natew]

Hi

 

Just do normal backups.

 

Retrospect uses "progressive backup". This is designed so the user doesn't have to worry about full/incremental backups. Retrospect manages that for you.

 

When a backup runs Retrospect looks in the backup set to see what files are already in there. It then compares those files against the disk you have chosen to back up. Any files that are not already in the backup set or that have changed since the last backup are copied into the backup data.

 

After the files are copied Retrospect takes a "snapshot" of the disk. The snapshot is a picture image of _all_ the folders and files on the disk. When you run a restore Retrospect uses the snapshot like a map to put files and folders back to the correct locations.

 

Basically - Retrospect copies only the files that need to be backed up but also takes a full image of your disk every time the backup runs.

 

Now to your question:

Retrospect keeps the most recent snapshot in the catalog file. To retrieve older backups click on the retrieve snapshot button.

 

Hope that helps

Nate

[Jumpmail]

Nate,

 

Thanks for your reply. I can't believe I have been missing that all of this time. The "Add Snapshot" button displays the dialogue that shows the previous snapshot. Thank you so much for your help! I do feel like an idiot now though

 

You Rock Nate!

 

One word of advice to Dantz -

It is crappy UI to not show all of the snapshots by default in the "Restore from Backup:Source" dialogue box. Even if you show the most recent 30 with an option to go back further it would be a help. The "Add Snapshot" button is not intuitive at all! How about "More Snapshots", or "Previous Snapshots"? A small thing to make your application a LOT more friendly. "ADD Snapshot" makes you think you would click on that to create a new backup script using that media... (in my case anyway).

[natew]

Hi

 

FWIW - there are some good technical reasons for not showing all the snapshots. Its a long story though...

 

Using the add snapshots menu takes some getting used to but it really is the best way.

 

Thanks

nate

[ozbill99]

Hi Dantz/EMC didn't need to change the terminology every-one was used to. Full backup is now recycle, and what the %$& does "normal" mean. It's either differernetial (which is - backup all new and changed since last FULL backup) or incremental (which is - backup all new/changed since last ANY backup).

 

To recover/restore, incremental requires all backup tapes back to last FULL (could be many tapes), differential requires Last FULL plus last differential (2 tapes).

 

Are you saying Dantz' Normal is actually a differential, however, to restore just needs the snapshot?

 

In that case, why would you ever do a FULL?? Unless it's to "trigger" the snapshot?

[nekr0phage]

Hi Bill,

 

Normal is more like incremental as it gets the new and changed files since the last backup to that backup set, not since the first backup.

 

And yes, to restore you only need to select one snapshot and Retrospect will do the rest. However, if you have data spread across several tapes, it will need to pull the corresponding data from those tapes.

 

Recycles generally are used to accomodate limited backup media, or to keep a limited backup history.

[ozbill99]

Hi Retro Addict,

 

What do you mean by "data spread across several tapes"? Spanning?

 

What exactly is in a snapshot?

 

Cheers

[nekr0phage]

Hi Bill,

 

Yes, I meant spanning, just couldn't get the word to come to me.

 

A snapshot is basically a picture of the source at the time of backup, it retains your directory heirarchy and, for OS volumes, contains system state information. There is a better description in the user's guide on page 26:

http://kb.dantz.com/display/2n/articleDirect/index.asp?aid=8333&r=0.8813135

[ozbill99]

It still doesn't make sense to me! By the way, that link doesn't work any more, I get "session timeout" when I try to access it, but I had an online copy, which I read but didn't clarify anything.

 

Let's say we have a library/autoloader with 10 tapes, each of which can easily hold a full backup with lots of spare room.

 

We start Retrospect on its first run to do a "Normal" backup to tape 1.

 

The next day, we do a "Normal" backup to tape 2, and so on to tape 10. What exactly is on tapes 2 to 10?

 

On the first pass, doesn't Retrospect "set" the Backup done "sticker" on all backed up file names. On pass 2, does it check all files for the backup done "sticker" set or reset to indicate the file has changed since the last backup, or does the Snapshot now do that function.

 

On pass 11, does the "normal" backup now to tape 1 append all files changed since pass 1 or since pass 10?

 

It's important because I would need to know how many tapes I would need to do a full restore to a new hard drive for instance.

 

If the sunbsequent backups "tapes 1-10 2nd time around" contain just "incrementals" there's no way the snapshot plus the previous day's tape can restore ALL the files to restore a complete hard drive.

 

From all the backup ap;lications I have had experience with, the backup plans would require a full backup, then the next part of the process would be one of 3 options, recycle (overwrite the tape), or incremental (append or write to new tape all the files created or changed since the last backup), or differential (append or write to new tape all files changed or created since the last FULL backup)

 

For restore purposes, the recycle method would require just one tape (the current one), the incremental would require the last full backup plus each tape since, while the differential method would require just 2 tapes if restore is required, the last full plus the last differential.

 

Do you agree? Which is the Retrospect method? Or is it an amalgam of 2 or all 3 methods?

 

Rgds

[rhwalker]

You are trying to fit the retrospect paradigm into the paradigm used by other programs. It's none of what you posit or it is all, depending on how you do it.

 

There is one way to do what you posit where each "normal backup" tape would be that day's full backup (to use the terminology of other programs). There's another way where you are wasting tapes, and each of the successive tapes will be incrementals over the first.

 

One way to tell is by the name of the tapes, which will be similar to the name of the backup set.

 

Retrospect names backup sets that move to new media as follows (assuming you gave the backup set a name of "My Backup Set":

My Backup Set[001]

My Backup Set[002]

My Backup Set[003]

 

This has nothing to do with the tapes - it's the names of the backup sets.

 

Tapes can be members of each backup set. So, for example, you could have members (tape names) of:

 

1-My Backup Set[001]

2-My Backup Set[001]

3-My Backup Set[001]

 

and

 

1-My Backup Set[002]

2-My Backup Set[002]

3-My Backup Set[002]

 

You haven't provided enough information to answer your question because you don't indicate whether the tapes are members of the same backup set. I'm not one to tell people to RTFM, but this is a case where you really do need to go back and carefully read the retrospect manual and understand the model of backup sets, members of backup sets, and snapshots.

 

Russ