I have been testing Restic, and I’ve come across an issue where the 2nd backup is as intensive and slow as the first backup. My test directory is 413GB, with 8448 directories, 150537 files.
The initial backup took something like 3 hours. During backup, CPU is close to 100% (it is a Celeron G1610T, so it’s not very powerful). After a successful initial backup (I have RESTIC_REPOSITORY and RESTIC_PASSWORD set):
ID Date Host Tags Directory
bdfbd30e 2017-09-08 16:54:17 piccolo D:\Data\Users
D:\Tools\Restic>restic backup D:\Data\Users
scanned 8448 directories, 150537 files in 1:10
Interrupt received, cleaning up
[1:15] 1.08% 60.705 MiB/s 4.480 GiB / 413.317 GiB 4813 / 158985 items 0 errors ETA 1:54:57
The repository is a local USB 3 drive (U:\Restic), and the source is a local SATA hard drive. This is on Windows 2012 R2, running the latest version of Restic as of a few days ago.
As you can see, the 2nd backup is going to take almost the same amount of time as the original backup. The CPU is very high (99%), and while the backup is running, Restic is reading through all the files (I checked on the Windows Resource Monitor):
Any ideas what is going wrong?