Bor Snapshot Restoration Steps
Overview

The instructions below will fully restore Bor's data directory by downloading each file and subdirectories individually. 
Use aria2 or wget to download all of the Bor files. Last, modify the ownership of the files so Bor can access them. 

wget, which is ultimate command line downloader. However, wget failed to accelerate download speed. 

For ultra fast downloading use aria2.  It is a utility for downloading files. aria2 supported HTTP(S) protocols. 
It tries to utilize maximum download bandwidth. 

Please download the file that will tell aria2c which files to download and which directory to save them to. Then, use aria2c to download all of the Bor files.

Backup, Download and Restore

1. Stop the bor services 

service bor stop
OR
systemctl stop bor.service

2.  Navigate to the directory with your chaindata store in it, then download the file containing which files to download. This file lists each file to download on the first line, followed by which directory to save it to. 

cd /var/lib/bor/data/bor/

wget https://snapshots.girnaartech.com/polygon/amoy-testnet/bor-amoy-testnet-files.txt

3. Take a backup of existing chaindata

cp -frvp chaindata <destination-backup-Directory>

4. Remove chaindata directory from /var/lib/bor/data/bor/

rm -r ./chaindata

5. Open tmux or use screen/nohup to keep downloading after you close your connection.

6. Download the files using aria2c. This will download up to 12 files at a time (-j 12) and will use up to 12 connections to the server (-x 12). The total download size is around 3GB, which can take 30-50 secondes depending on location and latency.

sudo aria2c -j 12 -x 12 --console-log-level=warn --auto-file-renaming=false --summary-interval=3600 -c -i ./bor-amoy-testnet-files.txt

OR you can use wget. which can take upto 10 min depending on location and latency. 

Create a timestamp with the current date and Download the files using wget:

TIMESTAMP=$(date +"%Y-%m-%d"); wget -q --show-progress -m -r -nH --cut-dirs=4 --no-parent --reject="index.html*" https://snapshots.girnaartech.com/polygon/amoy-testnet/bor/${TIMESTAMP}-bor-amoy-testnet/


7. This will download files with current user ownership. Change all files to be owned by bor and the nogroup group

sudo chown -R bor:nogroup /var/lib/bor

8. That's it! Start Bor and check the logs.