Author: Richard Language: text
Description: Can you please discuss capacity planning with ZFS and Snapshots? Timestamp: 2017-05-28 15:53:33 +0000
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  1. Without ZFS its easy, you can calculate your burn rate with observations over a few months and divide your free space by that amount.
  3. However with ZFS and snapshots, deleting a file does not necessarily free up space.  How can I estimate how much space is going to be freed up in 30 days / 90 days / 180 days from snaps shots expiring to consider in my capacity planning.
  5. As an example, if someone deletes a 1 GB file where the longest snapshot retention is 90 days, I know it will take 90 days for the space to become available.  But how do I determine these events have happened?
  7. I need to forecast that the space I have left now, plus the space that will be freed up each week from expired snapshots will leave enough space available for day to day operations.   And to detect an upcoming free space problem far enough in advance to allow time to procure new drives, install, and rebuild disk by disk with larger drives as I don't have additional drive bays to work with.
  9. Typical management doesn't want to spend money upfront to advert a problem when we have plenty of disk space at the moment and I can't state to management based on our retention policies we will run out of space in XX months.  I feel like I wont see it coming until its too late.
  11. Seems like there are all kinds of metrics that could be captured with snapshots and files.
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