This document describes WalB, a Linux kernel device driver that provides efficient backup and replication of storage using block-level write-ahead logging (WAL). It has negligible performance overhead and avoids issues like fragmentation. WalB works by wrapping a block device and writing redo logs to a separate log device. It then extracts diffs for backup/replication. The document discusses WalB'
![An Efficient Backup and Replication of Storage](https://cdn-ak-scissors.b.st-hatena.com/image/square/46327d7ad0ba4fd3c5d753f54bcc8b4262dc7f54/height=288;version=1;width=512/https%3A%2F%2Fcdn.slidesharecdn.com%2Fss_thumbnails%2Fwalb-linuxconjapan2013-130528061043-phpapp01-thumbnail.jpg%3Fwidth%3D640%26height%3D640%26fit%3Dbounds)