jspcto
Cadet
- Joined
- Oct 24, 2015
- Messages
- 8
Hi all... I'm looking for a little help understanding how replication can accomplish what is stated in the documentation here http://doc.freenas.org/9.3/freenas_storage.html#replication-tasks.
The part that confuses me is the second sentence about creating a backup of a dataset or pool. According to the documentation on Periodic Snapshots (excerpt below), snapshots only contain data which has changed.
So, if a replication task sends ZFS snapshots (which are only changes to the original dataset), how can it be an off-site backup as mentioned in the documentation? In the event of a catastrophic event, how could those snapshots be used to rebuild datasets if they only contain changes?
It is possible I'm confused about the intent of replication or the concept of snapshots, but I'm trying to better understand this feature and potentially apply it to my scenario. In short, I'd like to mirror selected datasets to an off-site FreeNAS server to help mitigate against catastrophic loss. I've looked at rsync as well, and I'm wondering if that might be better suited for this use case.
Thanks in advance for any light you can shed on this topic.
"A replication task allows you to automate the copy of ZFS snapshots to another system over an encrypted connection. This allows you to create an off-site backup of a ZFS dataset or pool."
The part that confuses me is the second sentence about creating a backup of a dataset or pool. According to the documentation on Periodic Snapshots (excerpt below), snapshots only contain data which has changed.
"A periodic snapshot task allows you to schedule the creation of read-only versions of ZFS volumes and datasets at a given point in time. Snapshots can be created quickly and, if little data changes, new snapshots take up very little space. For example, a snapshot where no files have changed takes 0 MB of storage, but as you make changes to files, the snapshot size changes to reflect the size of the changes."
So, if a replication task sends ZFS snapshots (which are only changes to the original dataset), how can it be an off-site backup as mentioned in the documentation? In the event of a catastrophic event, how could those snapshots be used to rebuild datasets if they only contain changes?
It is possible I'm confused about the intent of replication or the concept of snapshots, but I'm trying to better understand this feature and potentially apply it to my scenario. In short, I'd like to mirror selected datasets to an off-site FreeNAS server to help mitigate against catastrophic loss. I've looked at rsync as well, and I'm wondering if that might be better suited for this use case.
Thanks in advance for any light you can shed on this topic.