spirent avalanche

Cache penetration ConceptAccess to a nonexistent key, the cache does not work, the request will penetrate into the DB, when the traffic is large, the db will be hung off.Solution SolutionsUsing the bitmap filter, a large enough to store the key that may be accessed, the nonexistent key is filtered directly;Access key does not query the value in db, also writes null values to the cache, but can set a shorter expiration time.Cache Avalanche ConceptA lar

Cache avalancheThe cache avalanche may be because the data is not loaded into the cache, or the cache is invalidated by a large area at the same time, causing all requests to go to the database, causing the database CPU and memory load to be too high, or even downtime.Solution Ideas:1, using the lock count, or use a reasonable number of queues to avoid cache failure when the database caused too much pressure. This approach can alleviate the pressure o

Cache avalancheThe cache avalanche may be because the data is not loaded into the cache, or the cache is invalidated by a large area at the same time, causing all requests to go to the database, causing the database CPU and memory load to be too high, or even downtime.Solution Ideas:1, using the lock count, or use a reasonable number of queues to avoid cache failure when the database caused too much pressure. This approach can alleviate the pressure o

The cache Avalanche Cache Avalanche is due to the original cache invalidation (expired) and the new cache is not in the period. All requests to query the database, and the database CPU and memory caused great pressure, serious will cause database downtime. Thus forming a series of chain reaction, causing the whole system collapse. (1) In this case, the general concurrency is not particularly high time, the

cache penetration : Usually the cache is based on key to find value, if the cache does not exist, then go to the db to find, if found, the Key->value write to the cache. However, for some of the data that does not exist in the cache each time to find, so every time to find in DB, DB can not find so can't write cache, so reciprocating, then lost the meaning of the cache. WORKAROUND: The query is empty to db, but the cache expiration time of this data need to be set to a little bit; all possible

Since distributed systems make different types of services, in one system 1, different services may be called, such as services A, B, C, and the service and service will also call each other, such as service D, E will invoke service A; When service a fails to be invoked, System 1, Service D, and service e fail, resulting in a service avalanche due to a service problem that causes multiple systems or services to be unavailable. Therefore, a fuse is p

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1.Cache penetration:Query a data that does not exist. For example, to query an article table with a nonexistent ID, the database is accessed every time. If someone maliciously destroys the ID, it is likely to directly affect the database. Solution:

We used to have deep reverence for the words printed on paper. We once looked at experts and believed in authoritative institutions. The day before yesterday, I was playing a healthy TV program on the TV, saying that if there is a cross on the palm

Spirenttestcenter, the United States think Bollen Company's network testing instruments, covering the Ethernet L2~L7 layer, the use of the most powerful instrument.Automated test scenarios for 1.SpirentTestcenterTest the at frame on the PC---->TCL Driver Library SIG_TEQ_STC.TCL (load Spirenttestcenter Library)-----(Ethernet cable)----->STC ChassisSTC's Chassis internal command is also TCL format, but there is a disadvantage in debugging, script execution effect can not be immediately reflected i

group throughput, and latency of adding/exiting a stream, and forwarding tolerance capability forward pressure ). BKJIA editing Note: for the performance evaluation of vswitches under normal circumstances, note the following: features, application-level QoS Assurance, VLAN support, network management, and link aggregation, supports VRRP. In addition to the first two aspects, we have used the Spirent Test Center's fault generation/analyzer with 24 10

optimization of e-commerce website can not be separated from the stress test of simulating real environment. And think Bollen communication is the expert in this field. In recent years, Si Bollen based on Avalanche e-commerce website testing solution has been for many customers to complete this aspect of testing, such as: A telecommunications operator Hospital line system, a well-known large-scale video portal product booking/snapping system, an auth

functions, such as generating random numbers, conditional statements, cyclic statements, network connections, file read/write, and packet analysis. There is also the spirent automated test suite, which is user-friendly on the user interface and easy to configure and execute tests. We used to manage our own test cases in the same model. However, it is not open enough. It is not easy to develop two times above. You Need To Ask

This method includes 10 sets of tests covering L2 and L3 single propagation; IGMP Group Multi-Point propagation; L2 and L3 multi-point propagation; network access control (NAC)/802.1X; storm control; Energy consumption; vswitch manageability, security and practicability, and vswitch features. A detailed and complete method is provided. In the L2 single propagation performance test, we provide each switch with a single virtual LAN containing all ports. Attach the

Spring Cloud (iv): Service-tolerant Protection Hystrix "version Finchley" Posted in 2018-04-15 | updated on 2018-05-07 | In a distributed system, it is often the case that a basic service is unavailable, causing the entire system to become unusable, a phenomenon known as service avalanche effect. To cope with service avalanches, a common practice is to downgrade the manual service. And the advent of hystrix gives us another option. Hystr

latest test center Tester of Spirent for the first time, and conducted an in-depth test on several typical layer-3 switches on the market. The test results can be used as a reference for enterprises to select and deploy layer-3 switches. As the latest generation of Spirent testing equipment, TestCenter embodies the concept of overall testing. In the past, it was necessary to perform multi-service scenario

How to add in 1.cmdSET Path=%path%;c:\program Files (x86) \wiresharkNote: Add C:\Program Files (x86) \wireshark to the Windows environment variable as above codeHowever, the use of the Os.system () function in Python cannot execute the command, and no reason has been found yet.2.python operation Windows Registry make changesImport _winreg as Wgkey_test = WG. Openkey (WG. Hkey_local_machine,r "SYSTEM\CurrentControlSet\Control\Session manager\environment", 0,WG. key_all_access) PATH_STR = WG. Quer

has updated data a User A failed to delete cache for data a User B reads old data that is cached by data a At this point, the problem of inconsistent data arises.Solution Solutions1. Set the cache's effective time (the simplest scenario)Advantages: Simple Easy to operate Disadvantages: There will be old data in a short period of time If the amount of data is too large, the cache time is short, the cache is prone to a large number of failures during a

trend. Intelligent networks are affecting almost all network devices. Recently, layer-3 switches deployed on the edge of the network have seen significant changes. In this test, we used the latest TestCenter Tester of Spirent for the first time, and conducted an in-depth test on several typical layer-3 switches on the market. The test results can be used as a reference for enterprises to select and deploy layer-3 switches. As the latest generation of

In our daily work and life, there are an increasing variety of servers and server detection methods. This article aims to give readers a detailed introduction to the latest server testing methods. Here, the server testing method is divided into two major aspects: Performance Testing and functional testing. We have adopted a new test method for performance testing, which includes file testing, database performance testing, and Web performance testing. Among them, the file performance and database