The recent shift towards write-intensive workload on bigdata (e.g., financial trading, social user-generated data streams)has pushed the proliferation of log-structured key-value stores, represented by Google's BigTable , Apache HBase  andCassandra . While providing key-based data access with aPut/Get interface, these key-value stores do not support value-based access methods, which significantly limits their applicability in modern web and database applications. In this paper, we present DELI, a DEferred Lightweight Indexing scheme on the log-structured key-value stores. To index intensively updated bigdata in real time, DELI aims at making the index maintenance as lightweight as possible. The key idea is to apply an append-only design for online index maintenance and to collect index garbage at carefully chosen time. DELI optimizes the performance of index garbage collection through tightly coupling its execution with a native routine process called compaction. The DELI'ssystem design is fault-tolerant and generic (to most key-valuestores), we implemented a prototype of DELI based on HBasewithout internal code modification. Our experiments show that the DELI offers significant performance advantage for the write-intensive index maintenance.