基本硬件信息：
\n有问题的硬盘是 Seagate BarraCuda 4TB（型号：ST4000DM004）。hdparm -I有关更多详细信息，请参阅最后附录中的输出。
问题描述及测试：
\n问题从表面上看就像是缓存了要写入磁盘的数据，而写入速度却比这慢。然而，在这起案件中，事情似乎并没有那么简单。
Copying files (on an NTFS file system):
\nWhen writing a reasonably large amount of data, the performance of the drive will drop suddenly and sharply. Again, usually this would be as simple as caching files in RAM, then the disk working afterward for a while. Here, however, when monitoring the /proc/meminfo file (under Ubuntu), the observed behavior does not seem to support this. Even after writing the data …