Bridging the Gap: LLM-Powered Transfer Learning for Log Anomaly Detection in New Software Systems
Yicheng Sui, Xiaotian Wang, Tianyu Cui, Tong Xiao, Chenghao He, Shenglin Zhang, Yuzhi Zhang, Xiao Yang, Yongqian Sun, Dan Pei · 2025
For large IT companies, maintaining numerous software systems presents considerable complexity. Logs are invaluable for depicting the state of systems, making log-based anomaly detection crucial for ensuring system reliability. Existing methods require extensive log data for training, hindering their rapid deployment for new systems. Cross-system log anomaly detection methods attempt to transfer knowledge from mature systems to new ones but often struggle with syntax differences and system-specific knowledge, which hinders their effectiveness. To address these issues, this paper proposes LogSynergy, a novel transfer learning-based log anomaly detection framework. LogSynergy employs (1) LLM-based event interpretation (LEI) to standardize log syntax across different systems, and (2) system-unified feature extraction (SUFE) to disentangle system-specific features from system-unified features. These bridge the gap among different systems and enhance LogSynergy's generalizability. LogSynergy has been deployed in the production environment of a top-tier global Internet Service Provider (ISP), where it was evaluated on three real-world datasets. Additionally, we conducted evaluations on three public datasets. The results demonstrate that LogSynergy significantly outperforms existing methods. It achieves F1-scores over 89% on the real-world datasets and over 83% on the public datasets, using only 5000 labeled log sequences from the new system. These results underscore LogSynergy's effectiveness in rapidly deploying anomaly detection models for new systems. The code of LogSynergy has been open-sourced at https://github.com/DDUtian/LogSynergy