Author: ZIADI Mohamed Ali

How to install and mount XtreemFS in Linux

What is XtreemFS? XtreemFS is a fault-tolerant distributed file system adapted for different storage needs. It is characterized by it’s: Versatility : XtreemFS is an open-source technology that do not require special hardware of kernel modules. It is easy to maintain and deploy on Linux, Windows and OS X. Reliability : What makes XtreemFS among the best fault-tolerant file systems is it’s capability to  handel automatically faillures modes (even network split’s). Fault-tolerant replication keeps your data safe and gives you peace of mind. Scalability : Scalability is granted with XtreemFS according to your needs, simply by adding new standard hardware. You can start with a single server, grow to a cluster and even replicate across datacenters. Installation Debian/Ubuntu On Debian or Ubuntu add XtreemFS repository by editingf the file /etc/apt/sources.list  as below: deb <URL to repository> ./ Replace with the URL of the repository for your distribution. For example the packet source for the “Ubuntu 16.04” repository is: deb http://download.opensuse.org/repositories/home:/xtreemfs/xUbuntu_16.04 ./ Note : appending ./ to the URL is necessary. Add the package signing key of our repository to your system. As the key is currently the same for all distributions, you don’t have to change the URL to your distribution’s repository. wget -q http://download.opensuse.org/repositories/home:/xtreemfs/xUbuntu_16.04/Release.key -O - | sudo apt-key add - Update the package lists: sudo apt-get update Install the client or server package: sudo apt-get install xtreemfs-client...

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Redis : installation, configuration and replication in Linux

  What is Redis? According to wikipedia, REDIS (REmote DIctionary Server) is a software project that implements data structure servers. It is open-source, networked, in-memory, and stores keys with optional durability. According to monthly rankings by DB-Engines.com, Redis is often ranked: the most popular key-value database, #4 NoSQL database in user satisfaction and market presence based on user reviews, the most popular NoSQL database in containers, the #1 NoSQL database among Top 50 Developer Tools & Services. Installation Debian/Ubuntu root@debian7 # apt-get install redis-server Centos/Redhat/Scientific Linux root@centos7 # yum install redis root@centos7 # systemctl start redis # if you are using systemd Configuration and remarquable parameters The configuration file is /etc/redis/redis.conf for Debian/Ubuntu and /etc/redis.conf for Redhat Centos. The main remarquable parameters are : Listening address bind 127.0.0.1 Listening port port 6379 Daemonize or not the server daemonize yes Database number Set the number of databases. databases 16 Client number maxclient 3 Max memory maxmemory 128m Max memory policy Once the allocated maxmemory is consumed, Redis will process to key eviction. There are 5 different manners: volatile-lru -> remove the key with an expire set using an LRU algorithm : evict keys trying to remove the less recently used (LRU) keys first, but only among keys that have an expire set, in order to make space for the new data added allkeys-lru -> remove any key accordingly to the LRU...

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Memcached (Part – II) : How to test, troubleshoot and view stats

  In part I of this blog we saw how to install and test Memcached. In this part, we will see how to use this amazing software in command line. memcached-tool We can use the default script memcached-tool /usr/share/memcached/scripts/memcached-tool Usage: memcached-tool <host[:port] | /path/to/socket> [mode] memcached-tool 10.0.0.5:11211 display # shows slabs memcached-tool 10.0.0.5:11211 # same. (default is display) memcached-tool 10.0.0.5:11211 stats # shows general stats memcached-tool 10.0.0.5:11211 dump # dumps keys and values display /usr/share/memcached/scripts/memcached-tool 127.0.0.1:11211 display # Item_Size Max_age Pages Count Full? Evicted Evict_Time OOM 3 152B 11s 1 1 no 0 0 0 stats /usr/share/memcached/scripts/memcached-tool 127.0.0.1:11211 stats #127.0.0.1:11211 Field Value accepting_conns 1 auth_cmds 0 auth_errors 0 bytes 146 bytes_read 9363 bytes_written 22531 cas_badval 0 cas_hit's 0 cas_misses 0 cmd_flush 0 cmd_get 92 cmd_set 82 cmd_touch 0 conn_yields 0 connection_structures 7 curr_connections 5 curr_items 1 decr_hit's 0 decr_misses 0 delete_hit's 1 delete_misses 0 evicted_unfetched 0 evictions 0 expired_unfetched 0 get_hit's 87 get_misses 5 hash_bytes 524288 hash_is_expanding 0 hash_power_level 16 incr_hit's 0 incr_misses 0 libevent 2.0.19-stable limit_maxbytes 67108864 listen_disabled_num 0 pid 23989 pointer_size 64 reclaimed 17 reserved_fds 20 rusage_system 74.119732 rusage_user 94.034704 threads 4 time 1433928279 total_connections 52 total_items 82 touch_hit's 0 touch_misses 0 uptime 2940441 version 1.4.13 dump /usr/share/memcached/scripts/memcached-tool 127.0.0.1:11211 dump Dumping memcache contents Number of buckets: 1 Number of items : 1 Dumping bucket 3 - 1 total items add key3 1 1430987838 76 O:8:"stdClass":2:{s:8:"str_attr";s:13:"never_expires";s:8:"int_attr";i:333;} Making a...

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My name is Surendra Kumar Anne. I hail from Vijayawada which is cultural capital of south Indian state of Andhra Pradesh. I am a Linux evangelist who believes in Hard work, A down to earth person, Likes to share knowledge with others, Loves dogs, Likes photography. At present I work at Bank of America as Sr. Analyst Systems and Administration. You can contact me at surendra (@) linuxnix dot com.