NormalBackupOperations
So far we have seen just the first backup.
Here is a list of normal backup situations that needs to be covered.
Here is an example execution of zfs-backup.sh -b ExampleDocuments where some files have been added, modified, and deleted:
user@nas:~/src/zfs-backup$ ./zfs-backup.sh -b ExampleDocuments
####################################################################################################
ZFS Backup Script - server name = nas
####################################################################################################
Starting Zfs Backup - Backup operation requested.
Backing up zfspool/Documents to remote server backup as remote user buser on backuppool/DocumentsBackup
Latest Snapshot is zfspool/Documents@2024.07.26-00.48.47
Finding differences between zfspool/Documents@2024.07.26-00.48.47 and current status of zfspool/Documents - this could take some time...
There are differences -> creating a snapshot...
Creating snapshot...
Snapshot performed correctly: zfspool/Documents@2024.08.06-23.17.00
Current local snapshot = zfspool/Documents@2024.08.06-23.17.00
The dataset "DocumentsBackup" is already present in the REMOTE backup system.
Retrieving mountpoint for remote backup system dataset...
Remote backup system dataset mountpoint is: /mnt/storage
source pool = zfspool
source dataset = Documents
---
destination address = backup
destination username = buser
destination pool = backuppool
destination dataset = DocumentsBackup
####################################################################################################
=== Checking snapshot alignment between REMOTE and LOCAL systems
Last snapshot date on REMOTE system is : 2024.07.26-00.48.47
Last snapshot date on LOCAL system is : 2024.08.06-23.17.00
There is a snapshot with the same date on LOCAL system.
Finding all modifications from zfspool/Documents@2024.07.26-00.48.47 to zfspool/Documents@2024.08.06-23.17.00...
Determining changed files...
Determining moved files...
Determining deleted files...
There are 1 changed files, 6 deleted files and 1 moved files.
Remote is aligned with local? false
Calculating md5sums parallelizing 4x...
Computers / CPU cores / Max jobs to run
1:local / 2 / 2
Computer:jobs running/jobs completed/%of started jobs/Average seconds to complete
ETA: 0s Left: 0 AVG: 0.00s local:0/1/100%/0.0s
Fixing paths in md5sums file...
Substituting Documents with DocumentsBackup in md5sums file...
Calculating data transfer size approximation...
Approximate transfer size is 512
Sending snapshot...
receiving incremental stream of zfspool/Documents@2024.08.06-23.17.00 into backuppool/DocumentsBackup@2024.08.06-23.17.00
130KiB 0:00:00 [ 172KiB/s] [ 172KiB/s] [==============================================================================================================] 26056%
received 129K stream in 0.09 seconds (1.41M/sec)
Sending md5sums file to remote system...
md5-DocumentsBackup.txt 100% 62 60.1KB/s 00:00
Checking remote md5sums, please wait...
DocumentsBackup/NewFile.txt: OK
remote md5sum are correct.
Backup operations completed successfully.
user@nas:~/src/zfs-backup$
Of course, with such tiny modifications, the approximate transfer size is hugely underestimated, but you get the idea.
Here is the new list of snapshots on the nas machine:
user@nas:~/src/zfs-backup$ zfs list -t snapshot
NAME USED AVAIL REFER MOUNTPOINT
zfspool/Documents@2024.07.26-00.48.47 789K - 474M -
zfspool/Documents@2024.08.06-23.17.00 74.6K - 473M -
user@nas:~/src/zfs-backup$
And this is the new list of snapshots on the backup machine:
buser@backup:~$ zfs list -t snapshot
NAME USED AVAIL REFER MOUNTPOINT
backuppool/DocumentsBackup@2024.07.26-00.48.47 744K - 474M -
backuppool/DocumentsBackup@2024.08.06-23.17.00 0B - 473M -
buser@backup:~$
Here what the "Previous Versions" tabs look like for both nas and backup:
Here you can see that the dates are different. Files in red in the first snapshot have been deleted and do not appear in the second snapshot. There is a modified file in yellow. The new file is circled in green.
Same thing as before, but opening the two snapshots on the backup server:
Now let's see a different usage: no backup server involved, just a local NAS with several snapshots -> head on to Local Snapshots Only