它在HDFS中提供元数据服务。
控制协议同步元数据服务器和数据服务器之间的状态。
The control protocol synchronizes state between the metadata server and the data servers.
元数据服务器管理数据位置，以及在何处存储新数据。
The metadata servers manage the location of data and also where to store new data.
为了避免缓存过期，元数据服务器将收回不准确的布局。
To prevent stale caches, the metadata server recalls layouts that have become inaccurate.
系统由三个组件构成：中心服务、数据服务和元数据服务。
The system has three components: the Authority Service, the data Service, and the Metadata Service.
企业使用此功能可以将行业数据模型导出到元数据服务器中。
This feature enables the enterprise to export an industry data model to the metadata server.
元数据服务器管理inode空间，将文件名转变为元数据。
Metadata servers manage the inode space, converting file names to metadata.
分析表明，该方法很大程度上提高了元数据服务的可靠性。
The analysis results illustrate that such method enhances reliability of metadata service in great measure.
这个新的WSDL包含了代理中数据服务和元数据服务的位置。
This new WSDL contains locations of data and metadata services in the proxy.
在分布式存储系统中，元数据服务系统是一个潜在的访问瓶颈。
Metadata server system is a latent visit bottleneck in distributed storage system.
元数据服务器(cmds)的工作就是管理文件系统的名称空间。
The job of the metadata server (CMDS) is to manage the file system's namespace.
物理数据模型的生成也保留术语表分类，准备好发布到元数据服务器。
Generation to physical data model also retains glossary classifications, ready for publication to metadata server.
物理数据模型的生成也保留术语表分类，准备好发布到元数据服务器。
Generation to physical data retains glossary classifications, ready for publication to metadata server.
在大型分布式对象存储系统中，元数据服务系统是一个潜在的访问瓶颈。
In the large-scale distributed object-based storage system, the metadata service system is a latent visit bottleneck.
在某种意义上，数据服务和元数据服务仅仅是提供数据和元数据端点的工具。
The data and metadata Services are, in a sense, only utilities for providing data and metadata endpoints.
如图1所示，客户使用元数据服务器，执行元数据操作(来确定数据位置)。
As Figure 1 shows, clients perform metadata operations (to identify the location of data) using the metadata servers.
如图4所示，元数据服务器管理名称空间部分，可以(为冗余和性能)进行重叠。
As shown in Figure 4, the metadata servers manage portions of the namespace and can overlap (for redundancy and also for performance).
元数据服务是研究网格环境下数据库系统集成和访问技术所面临的关键问题之一。
Metadata service is one of the critical issues in the research of the database access and integration on the Grid.
这个动作允许元数据服务器将最近的元数据回馈给客户（这在元数据操作中很常见）。
This behavior allows the metadata server to serve recent metadata back to clients (which is common in metadata operations).
元数据服务器集群中必须负载均衡，以防某个元数据服务器成为存储系统访问的瓶颈。
Load balancing must be implemented in metadata server cluster in order to avoid any metadata server becomes the bottleneck of the system.
可以通过使用元数据服务，定期从SAP获取元数据，或者将元数据与 SAP 同步。
This metadata is obtained from and synchronized with SAP regularly by use of the metadata service.
在验证给定的LSID是否存在之后，我们返回包含单个位置(元数据服务的端点)的数组。
After verifying the existence of the given LSID, we return an array containing a single location: the endpoint of our metadata service. The following line needs some elaboration.
元数据服务主要是通过对MOF规范的研究实现了基于MOF的异构数据元数据的管理和存储。
Metadata service implemented the MOF based metadata management and storage of heterogeneous data through the research of MOF criterion.
如果客户机更改了这个文件，则会相应地更改布局的客户机实例，并且将所有更改提交回到元数据服务器。
If the client alters the file, the client's instance of the layout is duly modified, and all modifications are committed back to the metadata server.
当客户机不再需要这个文件时，它将提交剩余的更改，并将布局副本返回给元数据服务器，然后关闭文件。
When the client no longer needs the file, it commits any remaining changes, returns its copy of the layout to the metadata server, and closes the file.
PDB中心提供了一个元数据服务，来生成详细的RDF，联系两两LSID之间以及提供到外部资源的链接。
The PDB authority also offers a metadata service that generates comprehensive RDF that relates LSIDs to each other and provides links to external resources.
一系列服务器通过一个客户界面访问Ceph生态系统，这就明白了元数据服务器和对象级存储器之间的关系。
A set of servers access the Ceph ecosystem through a client interface, which understands the relationship between metadata servers and object-level storage.
研究分析了传统的元数据服务系统的管理模式，并且对传统的双元数据服务器系统的可靠性进行了理论分析。
It analyzes the traditional metadata service system, and analyzes the reliability of the traditional dual MDS by theoretical analysis.
这个日志对故障恢复也很有用：如果元数据服务器发生故障，它的日志就会被重放，保证元数据安全存储在磁盘上。
The journal is also useful for failure recovery: if the metadata server fails, its journal can be replayed to ensure that metadata is safely stored on disk.
元数据服务器将文件名转变为索引节点，文件大小，和Ceph客户端用于文件I/O的分段数据（布局）。
The metadata server transforms the file name into an inode, file size, and striping data (layout) that the Ceph client uses for file I/O.
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