Hi,
as pointed out by the article linked by @bricks those needs to be commented out like e.g.:
# save 900 1
# save 300 10
# save 60 10000
followed by a flush of redis, deletion of the dump file and a restart of redis.
Furthermore OpenVAS 8 might be affected by Community feed unusable - Greenbone Community Edition - Greenbone Community Forum as well. So it is really strongly suggested to migrate to the latest GVM-9 releases as pointed out by @bricks.