通过延迟分配，XFS赢得了许多机会来优化写性能。
By delaying allocation, XFS gains many opportunities to optimize write performance.
该延迟可以有助于减少与写日志记录相关的数据库管理器开销。
This delay can help reduce the database manager overhead associated with writing log records.
如果XFS没有延迟它的分配决定，那么，它也许已经不知不觉地将数据写到了多个非相邻块中，从而显著地降低了写性能。
If XFS hadn't delayed its allocation decision, it may have unknowingly written the data into multiple non-contiguous chunks, reducing write performance significantly.
在正常的环境中，一个写请求是直接写入到缓存中而不会引起延迟的，因为它不需要访问物理磁盘。
Under normal circumstances, a write request is written directly to cache and incurs no delay because physical disk access is not required.
但是，因为XFS延迟了它的分配决定，所以，它能够一下子写完数据，从而提高了写性能，并减少了整个文件系统的碎片。
But, because XFS delayed its allocation decision, it was able to write the data in one fell swoop, improving write performance as well as reducing overall filesystem fragmentation.
但这也是有代价的，那就是增加了写延迟，同时API中的一致性保证也发生了变化。
This was achieved at the expense of increased latency for writes and changes in consistency guarantees in the API.
使用延迟的随机写操作，当内存中的页面数量超过指定的数量，则将所有后续的页面写入到磁盘。
With random write behind, the number of pages in memory exceeds a specified amount and all subsequent pages are written to disk.
这种优化的关键是延迟物理块的分配，直到需要在磁盘上写这些物理块时才对其进行分配并写到相邻的块。
The key to this optimization is that by delaying the allocation of physical blocks until they need to be written to the disk, more blocks are present to allocate and write in contiguous blocks.
造成延迟的惟一原因是写线程太多，要等待很长时间才能获得锁。
The only reason for the delay could be that there are too many writer threads, and sufficient time has elapsed before a lock could be acquired.
write - behind的配置可以调整，以满足自己的运行环境，这其中包括写事务的比例，相同记录更新的频率，以及数据库的更新延迟。
The write-behind configuration should be tuned to best match your environment with regards to the ratio of write transactions, the same record update frequency, and database update latency.
对于JFS2，有更多文件系统性能改进，包括提前顺序页面读取以及延迟的顺序和随机写操作。
For JSF2, there are additional file system performance enhancements including sequential page read ahead and sequential and random write behind.
在使用延迟的顺序写操作时，在syncd守护进程运行之前，页面并不留在内存中，这可能会导致实际的瓶颈。
With sequential write behind, pages do not stay in memory until the syncd daemon runs, which can cause real bottlenecks.
如何写的工具类，以便我可以使用设计模式实现延迟加载？
How to write Utility class so that I can perform lazy loading with DTO design pattern?
因为这样的延迟不能容忍，我在写作部分如果可以检测管充满(在这种情况下，纠正我如果我错了，它将等待它有足够的空间写数据)。
Because such a delay can not be tolerated, I can detect on the writing part if the pipe is full (in which case, correct me if I'm wrong, it will wait for it to have enough room to write data).
第一个句子提醒了我我自己：我是有一段时间了写的意思，但我总延迟了它。
The first sentence reminded me of myself: I've been meaning to write for some time, but I've always delayed it.
即写即拷(或牛)技术完全延迟或防止复制的数据。
Copy-on-write (or COW) is a technique to delay or altogether prevent copying of the data.
即写即拷(或牛)技术完全延迟或防止复制的数据。
Copy-on-write (or COW) is a technique to delay or altogether prevent copying of the data.
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