【正文】 ualthreaded, so to the operating system the machine appears as a 32 way SMP. The processor speed is GHz. The p5 575connects to the outside world through two (2) Gigabit/s Ether interfaces. It also has its own dedicated DS4100 storage controller. (See below for a description of the DS4100.) Scaleout systems e in many different shapes and forms, but they is a BladeCenterH (BCH) chassis. We couple each BCH chassis with one DS4100 storage controller through a 2Gbit/s Fiber Channel link. The chassis themselves are interconnected through two nearestneighbor works. One of the works is a 4Gbit/s Fiber Channel work and the other is a 1Gbit/s Ether work. The cluster consists of 8 chassis of blades (112 blades in total) and eight DS4100 storage subsystems. The BladeCenterH chassis is the newest BladeCenter chassis from IBM. As with the previous BladeCenter1 chassis, it has 14 blade slots for blade servers. It also has space for up to two management modules, four switch modules, four bridge modules, and four highspeed switch modules. (Switch modules 3 and 4 and bridge modules 3 and 4 share the same slots in the chassis.) We have populated each of our chassis with two 1Gbit/s Ether switch modules and two Fiber Channel switch modules. Three different kinds of blades were used in our cluster: JS21 (PowerPC processors), HS21 (Intel Woodcrest processors), and LS21 (AMD Opteron processors). Each blade (JS21, HS21, or LS21) has both a local disk drive (73 GB of capacity) and a dual Fiber Channel work adapter. The Fiber Channel adapter is used to connect the blades to two Fiber Channel switches that are plugged in each chassis. Approximately half of the cluster (4 chassis) is posed of JS21 blades. These are quadprocessor (dualsocket, dualcore) PowerPC 970 blades, running at GHz. Each blade has 8 GiB of memory. For the experiments reported in this paper, we focus on these JS21 blades. The DS4100 storage subsystem consists of dual storage controllers, each with a 2 Gb/s Fiber Channel interface, and space for 14 SATA drives in the main drawer. Although each DS4100 is paired with a specific BladeCenterH chassis, any blade in the cluster can see any of the LUNs in the storage system, thanks to the Fiber Channel work we implement. 3 The Nutch/Lucene workload Nutch/Lucene [4] is a framework for implementing search applications. It is representative of a growing class of applications that are based on search of unstructured data (web pages). We are all used to search engines like Google and Yahoo that operate on the open Inter. However, search is also an important operation within Intras, the internal works of panies. Nutch/Lucene is all implemented in Java and its code is open source. Nutch/Lucene, as a typical search frame work, has three major ponents: (1) crawling, (2) indexing, and (3) query. In this paper, we present our results for the query ponent. For pleteness, we briefly describe the other ponents. Crawling is the operation that navigates and retrieves the information in web pages, populating the set of documents that will be searched. This set of documents is called the corpus, in search can be performed on internal works (Intra) as well as external works (Inter).Crawling, particularly in the Inter, is a plex operation. Either intentionally or unintentionally, many web sites are difficult to crawl. The performance of crawling is usually limited by the bandwidth of the work between the system doing the crawling and the system being crawled. The Nutch/Lucene search framework includes a parallel indexing operation written using the MapReduce programming model [2]. MapRed