Question:- Explain what is C10K problem?
Answer:- C10K problem is referred for the network socket unable to handle a large number of client (10,000) at the same time.
Question:- Mention what is the use of stub_status and sub_filter directives?
Answer:- • Stub_status directive: This directive is used to know the current status of Nginx like current active connection, total connection accepted and handled current number of read/write/wait connection • Sub_filter directive: It is used to search and replace the content in response, and quick fix for stale data
Question:- Explain does Nginx support compress the request to the upstream?
Answer:- You can compress the request to the upstream by using the Nginx module gunzip. The gunzip module is a filter that decompresses responses with “Content Encoding: gzip” for clients or servers that do not support “gzip” encoding method.
Question:- Explain how you can get the current time in Nginx?
Answer:- To get the current time in Nginx, you have to use variables from SSI module, $date_gmt and $date_local. Proxy_set_header THE-TIME $date_gmt;
Question:- Explain what is the purpose of –s with Nginx Server?
Answer:- To run the executable file of Nginx –s parameter is used.
Question:- Explain how to add modules in Nginx Server?
Answer:- During the compilation process, Nginx modules must be selected as such run-time selection of modules is not supported by Nginx.
Question:- What is Redis?
Answer:- Redis is an advanced key-value data store and cache. It has is also referred to as a data structure server as such the keys not only contains strings, but also hashes, sets, lists, and sorted sets. Companies using Redis includes StackOverflow, Twitter, Github, etc.
Question:- Explain the Replication feature of Redis?
Answer:- Redis supports simple master to slave replication. When a relationship is established, data from the master is transferred to the slave. Once this is done, all changes to the master
Question:- What are the advantages of using Redis?
Answer:- Advantage of using Redis are • It provides high speed • It supports a server-side locking • It has got lots of client lib • It has got command level Atomic Operation (tx operation)
Question:- What are the limitations of Redis?
Answer:- • It is single threaded • It has got limited client support for consistent hashing • It has significant overhead for persistence • It is not deployed widely
Question:- List out the operation keys of Redis?
Answer:- Operation keys of Redis include • TYPE key • TTL key • KEYS pattern • EXPIRE key seconds • EXPIREAT key timestamp • EXISTS key • DEL key
Question:- Which PHP module can be used with Redis?
Answer:- In PHP module, PRedis is more preferable than Redid PHP binding or Resident
Question:- Does Redis give speed and durability both?
Answer:- No, Redis purposely compromises the durability to enhance the speed. In Redis, in the event of system failure or crash, Redis writes to disk but may fall behind and lose the data which is not stored.
Question:- How can you improve the durability in Redis?
Answer:- To improve the durability of Redis “append only file” can be configured by using fsync data on disk. Fsync () every time a new command is added to the append log file: It is safe but very slow Fysnc() one time every second: It is fast, but you may lose 1 second of data if system fails Never fsync(): It is an unsafe method, and your data is in hand of Operating System