Ext4

You 'll find various improvements and innovations in the new ext4 file system .

在ext4文件系统中，您可以发现各种改进和创新。

Ext4 introduces numerous new advancements for performance , scalability , and reliability .

ext4在性能、伸缩性和可靠性方面进行了大量改进。

Ext4 borrows many useful concepts from a variety of competing file systems .

ext4从竞争对手那里借鉴了许多有用的概念。

Ext4 adds support for online defragmentation , which should improve overall performance .

Ext4支持在线磁盘整理，这能够改善总体性能。

Like ext3 , ext4 is a journaling file system .

和ext3一样，ext4也是一个日志文件系统。

In this way , you can migrate an ext3 file system online to an ext4 file system .

您可以通过这种方式在线将ext3文件系统迁移到ext4文件系统。

Ext4 includes numerous self-protection and self-healing mechanisms to address this .

但ext4通过许多自主保护和自主修复机制来解决这个问题。

Ext4 supports multiple modes of journaling , depending upon the needs of the user .

ext4支持根据用户需求采用多种模式的日志记录。

You can also gradually migrate a file system from ext3 to ext4 online with a mass change .

通过大规模的改变可以逐渐将文件系统从ext3迁移到ext4。

Delayed allocation Ext4 can delay allocating disk space until the last moment , which can improve performance .

延迟分配Ext4能够尽量延迟磁盘空间的分配，这能够提高性能。

You can find additional references to journaling an important aspect of ext4 in the Resources section .

在参考资料小节可以找到其他关于日志记录（ext4的重要部分）的资料。

As file systems scale to the massive sizes possible with ext4 , greater reliability concerns will certainly follow .

ext4文件系统可能会扩展得比较大，这将导致可靠性问题。

Most notably , ext4 supports file systems of1 exabyte in size .

最值得一提的是，ext4支持1EB的文件系统。

But even as ext4 addresses scalability and reliability , it provides a number of enhancements for improved performance .

但是，ext4不仅解决了伸缩性和可靠性，它还提供各种改善性能的方法。

A final optimization again , contiguous block related is the block allocator for ext4 .

这是最后一个与相邻块相关的优化，即针对ext4的块分配器。

Ext4 replaces ext3 's mechanism with extents to improve allocation and support a more efficient storage structure .

ext4使用区段取代ext3的机制，从而改善了空间的分配，并且支持更加高效的存储结构。

Amazingly , timestamps in the extended file system arena prior to ext4 were seconds based .

令人惊讶的是，ext4之前的扩展文件系统的时间戳都是以秒为单位的。

Ext4 is forward compatible in that you can mount an ext3 file system as an ext4 file system .

ext4与ext3是向前兼容的，这样就可以将ext3文件系统挂载为ext4文件系统。

Journal checksums Ext4 adds a checksum to the journal data , which improves reliability and performance .

日志checksumExt4给日志数据添加了检查和（checksum）功能，这能提高可靠性和性能。

For this reason , the minimum timestamp resolution in ext4 is1 nanosecond .

因此，ext4中时间戳的最小分辨率为1纳秒。

Ext4 permits preallocation without doing this , which can improve the performance of some database and multimedia tools .

而ext4允许提前分配，无需进行上述操作，这能提高某些数据库和多媒体工具的性能。

To fully take advantage of ext4 , a file system migration is necessary to convert and exploit the new ext4 format .

为了充分利用ext4的优势，必须实现文件系统的迁移，以转换和利用新的ext4格式。

Ext4 implements this through a new system call that preallocates and initializes a file of a given size .

ext4通过一个新的系统调用来实现这个目的，这个调用将按照特定的大小预分配并初始化文件。

One of the first visible differences in ext4 is the increased support for file system volumes , file sizes , and subdirectory limits .

ext4的一个明显差别就是它支持更大的文件系统、文件和子目录。

Extents in ext4 adopt a layered approach to efficiently represent small files as well as extent trees to efficiently represent large files .

ext4的区段采用分层的方法高效地表示小文件，并且使用区段树高效地表示大文件。

Ext4 permits exabyte file systems that can support larger numbers of files , larger files , and deeper directory structures .

Ext4允许使用exabyte文件系统，这种系统支持的文件数量更多、体积更大、目录结构更深。

Ext4 accomplishes this in a number of ways , going beyond ext3 limits and breaking new ground in areas of file system metadata management .

ext4以多种方式现实了强大的伸缩性，它的伸缩性超越了ext3，并且在文件系统元数据管理方面开辟了新领域。

Ext4 supports file systems of up to1 exabyte in size ( 1000 petabytes ) .

ext4支持的最大文件系统为1EB（1000PB）。

Going further , it 's possible to use your own favorite file system ( such as ext4 ) on top of a ZFS volume .

更进一步，可以在ZFS卷的顶端使用您自己最喜爱的文件系统（如ext4）。

To combat this , ext4 implements checksumming of the journal to ensure that valid changes make their way to the underlying file system .

为了解决这个问题，ext4对日志执行校验和，确保有效变更能够在底层文件系统上正确完成。