Measurement and Analysis of LDAP Performance
Measurement and Analysis of LDAP Performance
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LDAP 性能测量与分析
DOI：
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发表时间：
2000
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通讯作者：
D. Verma
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作者：
Xin Wang;H. Schulzrinne;D. Kandlur;D. Verma
轻型目录访问协议（LDAP）正被越来越多的分布式目录应用程序所使用。我们描述了一种用于分析LDAP目录性能的工具，并研究了在各种访问模式下LDAP目录的性能。在实验中，我们使用了一种为区分服务网络中的服务等级规范（SLS）管理而提出的LDAP模式。对服务器和客户端代码中的各个模块进行检测，以获取它们对整个系统延迟和吞吐量的贡献的详细情况。我们首先研究在默认实验设置下的性能。然后我们研究在确定可扩展性的因素中的重要性，即前端与后端进程、CPU能力以及可用内存。在高负载情况下，连接管理延迟在大多数情况下急剧增加并主导响应时间。发现TCP纳格尔算法会引入非常大的额外延迟，并且在LDAP服务器中禁用它似乎是有益的。发现CPU能力在限制LDAP服务器性能方面很重要，并且对于无法存储在内存中的较大目录，从磁盘的数据传输也起着重要作用。服务器性能随目录条目数量的扩展由后端搜索延迟的增加决定，而随目录条目大小的扩展受搜索结果的前端编码限制，并且对于内存不足的目录，受磁盘访问延迟限制。我们研究了不同的机制来提高服务器性能。
The Lightweight Directory Access Protocol (LDAP) is being used for an increasing number of distributed directory applications. We describe a tool to analyze the performance of LDAP directories, and study the performance of a LDAP directory under a variety of access patterns. In the experiments, we use a LDAP schema proposed for the administration of Service Level Specifications (SLSs) in a differentiated services network. Individual modules in the server and client code are instrumented to obtain a detailed profile of their contributions to the overall system latency and throughput. We first study the performance under our default experiment setup. We then study the importance of the factors in determining scalability, namely front-end versus back-end processes, CPU capability, and available memory. At high loads, the connection management latency increases sharply to dominate the response in most cases. The TCP Nagle algorithm is found to introduce a very large additional latency, and it appears beneficial to disable it in the LDAP server. The CPU capability is found to be significant in limiting the performance of the LDAP server, and for larger directories, which cannot be kept in memory, data transfer from the disk also plays a major role. The scaling of server performance with the number of directory entries is determined by the increase in back-end search latency, and scaling with directory entry size is limited by the front-end encoding of search results, and, for out-of-memory directories, by the disk access latency. We investigate different mechanisms to improve the server performance.