The growing value of data as a strategic asset has given rise to the necessity of implementing reliable backup and recovery solutions in the most efficient and cost-effective manner. The data backup methods available today on linux are not effective enough, because while running, most of them block I/Os to guarantee data integrity. We propose and implement Next4 - file system based snapshot feature in Ext4 which creates an instant image of the file system, to provide incremental versions of data, enabling reliable backup and data recovery. In our design, the snapshot feature is implemented by efficiently infusing the copy-on-write strategy in the write-in-place, extent based Ext4 file system, without affecting its basic structure. Each snapshot is an incremental backup of the data within the system. What distinguishes Next4 is the way that the data is backed up, improving both space utilization as well as performance.

翻译：数据作为战略资产的价值日益增长，使得以最高效且最具成本效益的方式实施可靠的备份与恢复解决方案成为必要。当前 Linux 平台上的数据备份方法效率不足，因为大多数方法在运行时为保障数据完整性会阻塞 I/O 操作。我们提出并实现了基于文件系统的 Next4 快照功能——该功能内置于 Ext4 文件系统中，可生成文件系统的即时映像，提供数据的增量版本，从而实现可靠的备份与数据恢复。在我们的设计中，快照功能通过在基于盘区（extent）的就地写入（write-in-place）Ext4 文件系统中高效融入写时复制（copy-on-write）策略来实现，且不影响其基本结构。每个快照均为系统内数据的增量备份。Next4 的独特之处在于其数据备份方式，既提升了空间利用率，又优化了性能。