Memory system and operating method thereof

Abstract

A memory system may include: a nonvolatile memory device; a write buffer; and a controller suitable for: checking whether first write data have been committed at a point of time that a flush operation is performed on the write buffer, separating the flush operation into first and second flush operations which do not overlap each other but are consecutive to each other, according to the check result, and performing the first and second flush operations, when the first write data grouped into a transaction and second write data, which are not grouped into a transaction, are mixed and stored in the write buffer according to the sequence of the write data, among the write data stored in the write buffer, the controller may select and may store the first write data which are committed, in a first storage region of the nonvolatile memory device during the first flush operation.