Longtime duplicacy user here, but I’ve managed to confuse myself thoroughly interpreting the check
and backup
results recently. This was whilst taking a second look at how efficiently duplicacy is deduplicating my data. I’d appreciate someone clearing things up for me
My setup:
2 Windows laptops and 1 Raspberry PI 4 acting as my NAS with 4 separate drives attached.
1 of the NAS drives is my local backup storage. I have 7 repositories across the laptops and NAS that all backup to this storage (either direct or via SFTP). I then copy the local storage offsite using duplicacy copy. I only use the duplicacy CLI (no gui, no web gui). I have scheduled jobs setup to run backups, checks, prunes etc all regularly.
So, onto my confusion. Consider the output from the latest backup (revision 19) of my laptop to the local storage:
2019-12-10 19:06:12.080 INFO BACKUP_END Backup for C:\Users\martin at revision 19 completed
2019-12-10 19:06:12.080 INFO BACKUP_STATS Files: 592948 total, 121,256M bytes; 4641 new, 12,019M bytes
2019-12-10 19:06:12.080 INFO BACKUP_STATS File chunks: 24497 total, 121,626M bytes; 493 new, 2,510M bytes, 2,491M bytes uploaded
2019-12-10 19:06:12.080 INFO BACKUP_STATS Metadata chunks: 45 total, 199,887K bytes; 38 new, 169,857K bytes, 50,699K bytes uploaded
2019-12-10 19:06:12.080 INFO BACKUP_STATS All chunks: 24542 total, 121,821M bytes; 531 new, 2,676M bytes, 2,541M bytes uploaded
As I understand it, this says it added 531 new chunks increasing storage usage by approx 2.5GB.
Then over on the NAS I run the check
command:
snap | rev | | files | bytes | chunks | bytes | uniq | bytes | new | bytes |
martins-laptop | 1 | @ 2019-11-22 22:51 -hash -vss | 608322 | 153,659M | 30815 | 140,970M | 55 | 85,428K | 30815 | 140,970M |
martins-laptop | 2 | @ 2019-11-23 19:00 -vss | 603336 | 153,663M | 30801 | 140,976M | 4 | 4,619K | 41 | 91,638K |
<SNIP>
martins-laptop | 17 | @ 2019-12-08 20:14 -vss | 593012 | 119,512M | 23427 | 107,103M | 1 | 2,748K | 1 | 2,748K |
martins-laptop | 18 | @ 2019-12-10 12:41 -vss | 592068 | 119,510M | 23422 | 107,105M | 37 | 50,598K | 51 | 90,776K |
martins-laptop | 19 | @ 2019-12-10 19:00 -vss | 592948 | 121,256M | 23724 | 108,577M | 56 | 205,812K | 1469 | 7,575M |
martins-laptop | all | | | | 36781 | 168,305M | 21312 | 97,687M | |
For that same revision 19 this seems to tell a different tale - 56 new (uniq) chunks for the storage at 205MB (or 1469 newly seen chunks for this snapshot id at 7.5GB).
It’s at this point I get confused. I haven’t really paid much attention to the stats part of check
before, but I’m not sure how to interpret these numbers (despite browsing through the forum and help) or why they seem so different to the backup report?
As a slight aside, if I want to know how much my storage usage is increasing by do I look at the uniq
columns or the new
columns in the check
stats report. My gut says the uniq
ones, but is that correct?