Sync between s3 7billion objects

What is the problem you are having with rclone?

I need to set up synchronization between two object storages in different locations, syncing 7 million objects from one bucket to another, with hash comparison. The synchronization needs to run every 4 hours. I'm struggling to find options that allow the process to complete within 2 hours. I've used transfers and checkers set to 900, as well as the fast-list option. On average, synchronization takes 4 hours, sometimes even longer. During synchronization, less than 10,000 objects are copied at a time, and the volume is under 5GB. Please suggest what options I could try adding to speed up the process.

Run the command 'rclone version' and share the full output of the command.

rclone v1.73.1

  • os/version: ubuntu 22.04 (64 bit)
  • os/kernel: 5.15.0-60-generic (x86_64)
  • os/type: linux
  • os/arch: amd64
  • go/version: go1.25.7
  • go/linking: static
  • go/tags: none

The command you were trying to run (eg rclone copy /tmp remote:tmp)

rclone sync src:backet dst:backet -vv --checksum --transfers=900 --checkers=900 --fast-list --log-file /logs/$(date -I).rclone.log

Please run 'rclone config redacted' and share the full output. If you get command not found, please make sure to update rclone.

[dst]
type = s3
provider = AWS
access_key_id = XXX
secret_access_key = XXX
endpoint = dst
acl = private

[src]
type = s3
provider = AWS
access_key_id = XXX
secret_access_key = XXX
endpoint = src
acl = authenticated-read
### Double check the config for sensitive info before posting publicly

A log from the command that you were trying to run with the -vv flag

2026/03/04 12:03:32 INFO  :
Transferred:      560.641 MiB / 560.641 MiB, 100%, 405.887 KiB/s, ETA 0s
Errors:                60 (retrying may help)
Checks:          22013856 / 22013856, 100%, Listed 44078563
Transferred:         6142 / 6142, 100%
Elapsed time:   4h52m28.3s

2026/03/04 12:03:32 DEBUG : 657 go routines active

welcome to the forum,

rent a cheap vm in the same region as the bucket.
run rclone on that.