InfluxDB disk size increase when backup process fails

Hi Community!

I am really wondering what happens to my influxdb OSS instance, or I hope someone else had already experience this and solve it. (upon searching on internet, I didn’t fine any answer)

So here is the scenario…
before backing up my database, I found that my “data” folder is “20GB” in size. once I run my “backup” process, I ended up fail on backup due to my storage issue on my USB, so I decided to change my USB with larger capacity. However, upon checking my “data” folder again, it became “96GB” in size now.
This is very strange since that was a huge spike of data. I tried to backup again using another USB, this time it fails again due to corrupt memory. and when I look again on my “data” folder, it became “105GB”.
For the 3rd time, I run my backup process again until it was finished. When I checked my “data” folder, it stays now on “105GB”.

So I ended up on my theory that the data or the size consumes by influxdb is increasing everytime the backup process fails.
I don’t know if this is normal or not, but probably not.

Version: Influxdb 1.8+
OS: Windows Server 2019
Edition: OSS
Hoping for your help.