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Basic Linux Storage and Scenario #1

Basic hint for remembering:  Primary + extended = max 4 partition can be created In Linux we can have only 4 primary partitions on the disk, after that you cannot able to create a primary partition, if you required then you can add extended partition, not possible after 4-primary partition even you have disk free space. Extended partition will be the container for the remaining partition, It can be created as many you want (up to 10) extended the partition. MBR – Maintaining the record of all existing partition Storage Scenario You have been given a task by your manager to plan for the future disk space requirement of your server. As a first step towards this task, you are required to find out the following information about your server. Please run appropriate commands to gather the information. Names of the disks attached to your server What are their sizes? How much of free space is left on each disk? For all above queries find below answer with commands: $ fdisk –l              //Display all disk which is attached to sever $ parted -l           //Print free -> checks how much free space left $ df –h                  // Display file system disk space usage. That is, it displays the total size, the used and available space for each of your mounted partitions. The h stands for “human-readable”. $ lsblk                    // list...

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AWS Database Migration Service (DMS)

AWS Database Migration Service (DMS) helps to migrate databases to AWS easily and securely either it may be on-premises or any other cloud vendor. The source/Live database remains fully operational during the migration. The service can migrate data between most widely used databases, such as Oracle to Amazon Aurora or Microsoft SQL Server to MySQL Benefits:–  Simple to use means there is no need to install any drivers or applications.–  Minimal Downtime AWS helps you to migrate your databases to AWS with virtually no downtime. All data changes to the source database that occur during the migration are continuously replicated to the target.–  DMS Service is fast and Easy to Set-up a migration task within minutes in the AWS Management Console.–  Resources are virtualized and pooled ensuring physical infrastructure.–  Rapid Scalability instantly allocates additional computing resources to meet demands.–  Lower Costs: infrastructure, energy/facility costs and by automation.–  Enhanced security with VPC and protection of information assets–  IT resources can be provisioned on demand. How it works: To perform a database migration, AWS DMS connects to the source database, reads the source data, formats the data for consumption by the target database, and loads the data into the target database. Most of this processing happens in memory, though large transactions might require some buffering to disk. Cached transactions and log files are also written to disk. AWS DMS creates the target...

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Does it affect if we increase max_connections in AWS RDS for MySQL?

AWS RDS t2-micro running MySQL 5.5 most of the time it gives “too many connections” error. As per the DB instance type t2-micro it allows 66 maximum connections concurrently. There is option to increase this max DB connection value by creating a DB parameter group for this Micro instance.  But does it affect when we increase DB connection without upgrading DB Instance type? Each connection carries the load of per-connection buffers as set by these parameters join_buffer_size sort_buffer_size read_buffer_size read_rnd buffer_size Changing the number of connections increases the amount of memory each connection can demand to this : (join_buffer_size+sort_buffer_size+read_buffer_size +read_rnd buffer_size) X max_connections Amazon has to set the number of connections based on each model’s right to demand a certain amount of memory and...

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When to switch to a bigger RDS instance (upgrade RDS Instance type)

You need to know what differences there in configuration between my.cnf and RDS DB-Parameter: All default MySQL settings that would normally be written in a my.cnf. All values are the same in RDS with the exception of two which are mention below: ·         max_connections ·         innodb_buffer_pool_size Amazon set the following values based on server model: If your CPU is averaging > 70% or so, you might want to start planning on an upgrade. Before Upgrading your Box, ensure below check points:|-> Ensure how much DB connection min required by your application|-> Ensure NO Slow Query running more than 10sec|-> Ensure is any scripts making more DB connection with query for select / update / alter etc…|-> Is there any network latency between DB and...

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Change ulimit values permanently for a user or all user in Linux

The ulimit is a mechanism for restrict the amount of various resources a process can consume. There’s a shell command to set the ulimit for processes which are started in that shell. It will provide control over the resources a user or a process in a shell can use.  You can list the current setting of ulimit values by login as your user and type the following commands # ulimit –Hn 4096 # ulimit –Sn 1024 Default values should be 4096 and 1024 respectively. ulimit -Sv 500000     # Set ~500 mb limit So it will also determine the number of open files a user can open or edit. For increasing the ulimit, you need to change those parameters in a configuration file called vi /etc/security/limits.conf     * hard nofile 50000  // we have mention to all user(*) * soft nofile 50000 // we have mention to all...

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