Hi,

I need assitance from the forum gurus on how continuous incrementals with Image Manager might be a good solution for my clients - as opposed to backup retention defined in the job.  I am using SP SBS Server 3.2 with Image Manger 1.0.25.3.  My thought process is that a 1TB external USB HDD is going to hold more data history using collapsed daily and weekly images that if I perform a full backup each week with incrementals between.

So here goes.  If I setup a job to take continuous incrementals during the weekdays (every hour between 9am-6pm) the first job will take a full backup image (base SPF) file for each partition.  Thereafter an incremental SPI file will be created each hour for each partition.  I then setup an Image Manager with the following policy (Collapse job starts @ 8:30pm, Mins between collapse = 60, Keep incrementals = 7 days, daily = 30 days, weekly = 90 days).  Removal policies unchecked.  So my understanding thus far of what Image Manager will do (based on the above config) is as follows.

At 8:30pm Mon-Fri all my daily incrementals are collapsed into a single -cd file for each partition.  Only incrementals older than 7 days are removed from the backup disk.  Therefore my clients can only go back to their hourly incrementals for 7 days from the current date.

Once a week these dailies are collapsed into a weekly (-cd-cw) which stores all previous daily collapses into a single weekly collapse for each partition.  The dailies are kept for 30 days at which time they too are removed from my backup disk.  The client can only go back 30 days to an "end of day" backup from the current date.  They can still go back to their hourly incrementals for the preceeding 7 days as well.

Then after 90 days the older -cd-cw files are removed from the system.

So if my understanding is correct, what happens when I need to perform any restore operation but my older weeklies are missing due to my policy removing them after 90 days.  The original base SPF files will still be on the backup drive but I will only have the last 90 days of weeklies stored.  Will the image "chain" be preserved or do I still need to have a backup of EVERY weekly image from the time that Image Manager policy is activated?  Or after the 90 days is everything collapsed back into a new full backup (SPF) image?

 I hope this makes sense.  Thanks in advance for anybody who can set me straight on this.

 O.

The only thing missing in your description is the monthly collapse (-cd-cm, or -cd-cw-cm) which occurs each month based on the create time of the earliest full backup image in the directory.  These monthly collapse files always remain in the directory so beyond the 90 day period of weekly image files, the chain continues back to the base with -cm files.

One other thing, the check box to remove old incrementals or not only applies to the original files created by ShadowProtect.  The collapse files -cd and -cw are always moved from the destination directory to a subdirectory, "/Incrementals", where they can be deleted or archived manually.  ImageManager does a dependency verification before moving these collapse files to ensure the remaining files form a complete chain, but before actually deleting these files the user has an opportunity to do a full data verify of the current chain.  For example, if a -cw file older than 30 days fails to verify, you can use the -cd files that have been removed to recover the chain.

Thanks Doug, starting to make sense now.  So these monthly collapses are formed automatically from all available -cd/-cw files available at the time the -cm collapse process runs - correct?

How long are these -cm files kept before being removed/archived (if at all) to the /incrementals folder?

Lastly Is there ever a time when the continuous incremental job will run a new full backup - assuming it still does so if it cannot find a full (SPF) in the destination location.

Yes, -cm files are created from the chain of -cd/-cw files back to the previous -cm file or back to the base when the first -cm file is created.

-cm files cannot be moved to the /incrementals folder since this would break the chain of image files.

The continuous incremental job will not automatically create a new full backup like the weekly and monthly schedules. Instead, the error is written to the log and the job terminates.  You can manually start a new full backup at any time, just no automatic full backups after the initial full backup.

Hi Doug,

Okay no -cm's created yet.  The first (full) image was taken on the 18 June 2008 but so far no -cm file have been created.  Can you just clarify for me when the -cm is created?  Am I to expect a -cm to be automatically created a certain number of days after the full backup (and the recurring every x days thereafter)?  Is it on the last day of the month?  How does SP calculate when to create the -cm

 Thanks

SP uses the day and time the full was created to calculate the create time of the -cm file.  In your case the -cm file will be created on the 19th of every month using the incremental files through the end of he 18th of each month.  The collapse will occur at the same time during the day that the full was created.

I think I am off by a day.  I think the -cm file will be created on the same day of the month the full was created and will include all incrementals through the end of the previous day.

Thanks Doug, I can confirm the -cm file was created on the 18th July.  The original full image was created on 18th June so I'm guessing that all future monthlys will be created on the 18th of each month.