So, why exactly does XFS have allocation groups?
那么，XFS到底为什么要有分配组呢？
Primarily, XFS USES allocation groups so that it can efficiently handle parallel IO.
主要原因是，XFS使用分配组，以便能有效地处理并行io。
As you'll recall from my previous article, allocation groups let XFS perform multiple metadata operations in parallel.
正如您将从我前一篇文章所回忆的一样，分配组让XFS并行执行多个元数据操作。
So rather than let mkfs.xfs choose the number of allocation groups for your filesystem, specify a number by using the -d agcount=x option.
因此，不要让mkfs.xfs为您的文件系统选择分配组的数目，而是通过使用 -d agcount=x 选项指定一个数目。
The second option lets you enhance the performance of your new filesystem by telling mkfs.xfs to minimize the number of allocation groups that are created.
第二个选项通过告诉mkfs.xfs 将创建的分配组的数目最小化，让您增强新文件系统的性能。
Thanks to allocation groups, the XFS code will allow multiple threads and processes to continue to run in parallel, even if many of them are performing non-trivial IO on the same filesystem.
多亏了分配组，XFS代码将允许多个线程和进程持续以并行方式运行，即使它们中的许多线程和进程正在同一文件系统上执行大规模IO 操作。
Allocation groups also help to optimize parallel IO performance on multiprocessor systems, because more than one metadata update can be "in transit" at the same time.
分配组还有助于在多处理器系统上优化并行io性能，因为可以同时有多个元数据更新处于“在传输中”。
Allocation groups also help to optimize parallel IO performance on multiprocessor systems, because more than one metadata update can be "in transit" at the same time.
分配组还有助于在多处理器系统上优化并行io性能，因为可以同时有多个元数据更新处于“在传输中”。
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