bug(hubble.sh): down/up clears grafana stats

[sanjayprabhu]

What is the bug?
from vrypan:

  653  2023-10-26 17:24:37 cat hubble/hubble-autoupgrade.log
  654  2023-10-28 19:27:49 cd hubble/
  655  2023-10-28 19:27:52 ./hubble.sh logs
  656  2023-10-28 19:28:00 ./hubble.sh up
  657  2023-10-30 19:09:55 cd hubble/
  658  2023-10-30 19:09:58 ./hubble.sh logs
  659  2023-10-30 19:10:09 ./hubble.sh down
  660  2023-10-30 19:18:45 ./hubble.sh up
  661  2023-10-30 19:22:45 sudo docker system prune
  662  2023-10-30 20:28:39 df -h
  663  2023-10-31 09:34:55 ls -l
  664  2023-10-31 09:35:03 cat hubble-autoupgrade.log

Is it possible that down + up, removes the stats?
The timestamp when data start again is a couple of minutes after history 660.
I did 661 after the logs showed that the hub was up and messages were comming in.

How can it be reproduced? (optional)
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