Which of the following statements are correct, with regard to Alibaba Cloud Log Service? (Number of correct answers: 3)

Which of the following statements are correct, with regard to Alibaba Cloud Log Service? (Number of correct answers: 3)
A . As an agent for collecting logs, Logtail can collect logs from existing system log files in a non-intrusive manner
B . The Log Service frontend service adopts an LVS + NGINX architecture
C . The Logstore backend service is deployed on a single machine to complete the real-time persistence, indexing, query and delivery of Logstore data to MaxCompute
D . Each log written to the Log Service backend will be saved in triplicate (across three separate physical servers)

Answer: B,C,D