What are popular / good NoSQL databases?
What are the popular / good NoSQL databases nowadays?
MongoDB, CouchDB
Find more at https://en.wikipedia.org/wiki/NoSQL and http://nosql-database.org/
What are the popular / good NoSQL databases nowadays?
MongoDB, CouchDB
Find more at https://en.wikipedia.org/wiki/NoSQL and http://nosql-database.org/
How to clean the commit history of a repository in both of my locally cloned copy and the copy on the git server so that only the files after the last commit are left? git works in branches. Here, we assume removing the history of the master branch. One solution is doing as follows. Rename…
We have many hosts with internal IPs like 10.0.3.* behind a gateway, say gateway.example.org. The hosts with internal IP connect to the Internet through the gateway. How to directly SSH to hosts using internal IPs through the gateway? Here is the solution: Directly SSH to Hosts with LAN IPs Through the Gateway Read more: Directly…
The public cloud storage services like Amazon S3, Google Cloud Storage and Windows Azure Storage replicate the data to ensure high availability. On the other hand, with data being replicated, the storage services exhibits certain data consistency models. Different cloud service providers employ different data consistency models nowadays. In this post, we survey the data…
stop-dfs.sh report that there are no datanodes running on some nodes like hdfs-node-000208: no datanode to stop However, there are DataNode process running there. How to clean these processes on many (100s) of nodes? You may use this piece of bash script: for i in `cat hadoop/etc/hadoop/slaves`; do echo $i; ssh $i ‘jps | grep…
I wanna migrate leveldb (code.google.com/p/leveldb) to my github repository. Create a new repo on github.com with this link https://help.github.com/articles/creating-a-new-repository git clone https://code.google.com/p/ project-name.git Set the remote origin url as follows: git remote set-url origin https://github.com/ username/ repo-name.git git pull to pull the latest. git push origin master after making local changes. This is the original…
How to calculate the average of value in lines of a text file on Linux by a script? The file.txt is like: Run 0: Time used: 22.235331711 seconds. Run 1: Time used: 20.784491219 seconds. Run 2: Time used: 21.851638876 seconds. What I want it to calculate the average time. awk is handy for this purpose:…