While I appreciate ZFS and its snapshot feature, it would be helpful to have basic status information displayed about the snapshot process, indicating whether it has been started, failed, or completed successfully, especially considering that I have observed snapshot times on my device (i5-6600T processor, 16 GB of RAM, and an SSD) ranging from 0.5 to 3 hours.
To my knowledge snapshots are instant and cheap. What problem are you looking at?
Cheers,
Franco
What are you talking about, snapshot to take up to 3h?
As Franco said, its instant. Are you sure its snapshots you are creating/running?
Regards,
S.
Thanks for replying to the post!
I am relatively new to ZFS and may have misunderstood the snapshot process.
I noticed that after clicking the "Save" button, the snapshot entry and its creation date are displayed instantly and are final. However, the size of the image continues to increase over a period of 0.5 to 3 hours until it reaches its final size. I refreshed the GUI periodically until I felt confident that the process was complete, and only then did I activate the new snapshot, update the software, and/or reboot the system, trying to avoid any data loss or consistency issues.
If the snapshot is an instant action, does this mean I don't have to worry and can immediately activate the new snapshot, update the software, and/or reboot without facing negative consequences?
In other words, can I ignore the snapshot size displayed, knowing that it will be adjusted even if I interrupt the process by rebooting? Will it eventually show its final and correct value later on?
Cheers,
nettraveller
ZFS snapshots only set a point in time to which you can roll back. What you observe is new data that is being written all of the time, like RRD and netflow data or log files which increase the used space. IDK how you see the "image increase".
The overhead of having a snapshot will only show after the snapshot, in that every modification is done by copy-on-write and the original content is kept until the snapshot is deleted. So, having a snapshot prevents re-use of the old data.
So, the short answer is yes, you can upgrade immediately after the snapshot. If you are short on disk space, you should delete your snapshots later on, because the will grow over time with anything that will be written after they have been created (i.e. they have no fixed size).
This resource might be helpful:
https://www.truenas.com/docs/references/zfsprimer/