Rolling snapshot size

[Paul D Mallett]

Hi, If I set up five day rolling snapshots does the start date reset itself or do the snapshots get bigger and bigger. If the data set changes by 10% a day I would expect the first snapshot size to be about 10% of the original and the next 20% but will the sixth snapshot drop back to about 10% or will it rise to 60% or have misunderstood the nature of snapshots?

 

[depasseg]

misunderstood the nature of snapshots

This^^

Snapshots build on each other so to speak, and when you expire or delete the snapshot the files that are still relevant get rolled into the others (for instance if your second snapshot still refers to active files, the pointers from the first snapshot get corrected. If, OTOH, you deleted the file prior to the second snapshot, then those snapshot changes don't need to be rolled into the second snapshot and they just go away.

 

[Paul D Mallett]

So, the rolling snapshots will maintain a record of change in a file indefinitely so long as the original file still exists?

 

[depasseg]

So, the rolling snapshots will maintain a record of change in a file indefinitely so long as the original file still exists?

Not quite, the snapshots needs to exist as well. Otherwise the changes captured in the snapshot get merged into the next snapshot For simplicity, what ever changes that snapshot contained will disappear, but whatever changes exist in follow-on snapshots will remain.

 

[Paul D Mallett]

To say that I understand all that is probably an exaggeration but I think I have arrived back at the vague grasp I started with. Thanks for taking the time to explain.