Category Archives: Uncategorized

Preparing for a System Design Interview: Focus on Trade-offs, Not Mechanics

Are you getting ready for a system design interview? It is critical to approach it with the proper mindset and preparation. System design deals with components at a higher level, so staying out of the trenches is vital. Instead, interviewers are looking for a high-level understanding of the system, the ability to identify key components and their interactions, and the ability to weigh trade-offs between various design options.

During the interview, pay attention to the trade-offs rather than the mechanics. You must make decisions about the system’s scalability, dependability, security, and cost-effectiveness. Understanding the trade-offs between these various aspects is critical to make informed decisions.

Here are a few examples to prove my point:

  • If you’re creating a social media platform, you must choose between scalability and cost-effectiveness. Should you, for example, use a scalable but expensive cloud platform or a less expensive but less scalable hosting service?
  • When creating an e-commerce website, you must make trade-offs between security and usability. Should you, for example, require customers to create an account with a complex password or let them checkout as a guest with a simpler password?
  • When designing a transportation management system, you must balance dependability and cost-effectiveness. Should you, for example, use real-time data to optimise routes and minimise delays, or should you rely on historical data to save money?

Docker – Essential Commands

docker psList all running containers
docker ps -aList all containers stopped, running
docker stop container-idStop the container which is running
docker start container-idStart the container which is stopped
docker restart container-idRestart the container which is running
docker port container-idList port mappings of a specific container
docker rm container-id or nameRemove the stopped container
docker rm -f container-id or nameRemove the running container forcefully
docker pull image-infoPull the image from docker hub repository
docker pull Pull the image from docker hub repository
docker exec -it container-name /bin/shConnect to linux container and execute commands in container
docker rmi image-idRemove the docker image
docker logoutLogout from docker hub
docker login -u username -p passwordLogin to docker hub
docker statsDisplay a live stream of container(s) resource usage statistics
docker top container-id or nameDisplay the running processes of a container
docker versionShow the Docker version information

Setting storage driver in docker


Linux distributionRecommended storage driversAlternative drivers
Docker Engine – Community on Ubuntuoverlay2 or aufs (for Ubuntu 14.04 running on kernel 3.13)overlay¹, devicemapper², zfsvfs
Docker Engine – Community on Debianoverlay2 (Debian Stretch), aufs or devicemapper (older versions)overlay¹, vfs
Docker Engine – Community on CentOSoverlay2overlay¹, devicemapper², zfsvfs
Docker Engine – Community on Fedoraoverlay2overlay¹, devicemapper², zfsvfs

Get the current storage driver:

docker info

Set the storage driver explicitly using the daemon configuration file. This is the method that Docker recommends.

sudo vi /etc/docker/daemon.json

Add the details of storage driver in the daemon configuration file:

  "storage-driver": "devicemapper"

Restart Docker after editing the file.

sudo systemctl restart docker
sudo systemctl status docker

My 1st UDEMY course on Step-by-Step Instructions for Creating a Physical Standby Database (RMAN Active dupication)


Kindly enroll this course and give me your valuable suggestion, so I can improve the content of the course accordingly:

This course is not detailing about what is Oracle Dataguard but it help you to build a Physical Standby as quick as possible for your further practices

What are the requirements?

Basic knowledge of Database Administration
Standard laptop / desktop for practicing course assignments
Windows / Mac / Linux PC, Minimum 8 GB RAM and 100 GB HDD Storage
Virtualization software VirtualBox – Create two machines
OEL 5.9 / 6.5 ISO image file to install Linux on Virtual Box

What am I going to get from this course?

Database creation using DBCA.
Preparing the Primary Database for Standby Database Creation.
Preparing the Standby system
Step-by-Step Instructions for Creating a Physical Standby Database (RMAN Active duplication)
Post-Creation Steps.
Bonus Topic: Oracle 12CR2: Creating PDBs from the Seed.

What is the target audience?

Anyone who would like to learn Oracle Data Guard Technology
On job people, who are looking to get a guidance to create a Physical Standby Database


As part of our ERP implantation in our office, I made this document check list, hope it may help other also


Financial Accounting

*    Multi Company
*    Business Activities
*    Multi Projects / Departments
*    Multi Stores
*    Multi Currency

Software features:

*    Chart of Accounts
*    Accounts Initialization with opening balance
*    Vouchers
*    Payment
*    Receipt
*    Journal
*    Debit Note
*    Credit Note
*    Purchase
*    Sales
*    Purchase Return
*    Sales Return
*    Petty Cash
*    Post Dated Cheques handling (Both Issued and Received)
*    Recurring JV for differed revenue and expenses
*    BRS – Bank reconciliation statement
*    Payables & Receivables
*    Invoice wise payments and receipts allocation
*    Statement of account
*    Outstanding statement of account
*    Aging analysis
*    Following Financial Statements in combination (Company wise, Division /
*    Activity wise & Project / Department wise):
*    Trial Balance
*    Profit & Loss
*    Balance Sheet

Fixed Assets management Module

*    Add “n” number of fixed asset categories
*    Add “n” number of fixed assets under each categories
*    Asset details like Name, Purchase price, Life in years, ***Straight line method.
*    Monthly auto depreciation for all Fixed assets
*    Depreciation and Accumulated depreciation
*    Related auto chart of accounts creation and posting
*    Fixed Asset register (Summary)
*    Related Auto Accounting integration

PDC Management Module

*    Issued PDCs and Received PDCs from payment and receipt vouchers.
*    Auto posting of cleared PDCs.
*    Monthly break down of PDCs with sub totals.
*    PDC Remainders with various options.
*    PDC Bouncing, Re-submitting & Returning.
*    Related auto Accounting integration.


*    Marketing:
*    Leads generation sources, lead analysis, comparison of results with planned results.
*    Pre-Sales:
*    Lead entry, lead distribution (auto & manual), lead follow-up, creating contacts,accounts, converting leads into potentials, products (Items), quotation, sales order,
*    Sales staff commissions, Sales targets planning (monthly, quarterly & yearly),
*    Generating variance reports (Actual sales vs Planned) Sales person wise etc.
*    After Sales:
*    Recording cases from customers, case distribution to customer care executives by customer care managers, tracking the cases until it is closed.


*    Items which needs actions: tasks, events, reminders & follow-ups management. These modules are linked with other modules where ever required or applicable.

*    Dash Boards:
*    Role wise with graphs, important information, alerts and action items (activities).

*    Quick glance of MIS reports.

*    Documents filing:
*    Documents related to different modules can be attached with those records. These
*    documents can be searched on different parameters, viewed and printed.


*    e-mails sent history through the system related to different modules can be attached
with those records. These e-mails can be searched, viewed and printed.

Work Flow:

*    Approval process by different users/roles.

Trading Activity & Inventory

*    Sales and Purchase process (Trading)
*    Enquiry from Customers
*    Enquiry to Suppliers
*    Quotation from Suppliers
*    Quotation to Customers
*    Purchase Order from Customers
*    Purchase Order to Suppliers
*    Delivery from Suppliers (MRN)
*    Delivery to Customers(DO)
*    Invoice to Customers
*    Invoice from suppliers
*    Receipts from Customers
*    Payments to Suppliers

Inventory Management
*    Material
*    Category and Sub Category
*    Store
*    Items Qty , Rate & Amount
*    FIFO & LIFO
*    Opening Stock
*    Closing Stock (Stock on hand)
*    Minimum Reorder Level
*    Batch code
*    Item in & out history
*    Shelf Ref (Search)
*    Movement (Transfers) Between Stores

*    Sales Analysis by
*    Company
*    Division
*    Department
*    Sales Person
*    Product category
*    Customer
*    Supplier
*    Daily, Weekly, Monthly, Quarterly and Yearly.
*    Fast moving items
*    Slow Moving items
*    Gross Profit (GP) and GP margin report
*    Invoice wise GP and GPM report
*    Stock value report
*    Product in and out with running balance history report.

Services Activity

*    Enquiry from Customers
*    Quotation to Customers
*    Purchase Order from Customers
*    Delivery of service to Customers (DO)
*    Invoice to Customers
*    Receipts from Customers
*    Material Cost ( from Procurement and Inventory module)
*    Labor Cost (From HR, Time sheet and payroll Module)
*    Sub Contractor (From Sub Contractor Module)
*    Plant and Machinery ( From Plant and Machinery Module)
*    Miscellaneous ( From Different vouchers)
*    Comparing Original BOQ with Actual (Variance analysis)
*    Job / Project wise Profit analysis

HR& Payroll:

*    Employee Documents expiry alert
*    Employee general details
*    Employee Salary details (Basic, allowances, Deductions)
*    Loans management
*    Payroll processing and accounts integration
*    Pay sheet and Pay slips
*    Leaves management
*    Air Ticket management
*    Leave Salary management
*    Gratuity calculations
*    Service end process and settlement report

Fleet Management

*    Vehicle Details
*    Vehicle Service Details and schedules
*    Documents and license expire alerts
*    Expenses Details

Security and Administration

*    Administration and security
*    Multi-level security and access permissions
*    View, Add, edit and delete permissions
*    New user group creation
*    New user creation (Login & Password)
*    Data Backup & Recovery
*    Recording of user name with date and time for each transaction
*    Audit trial: User wise Activity (new, edit, delete) tracking of different documents.

*** Straight Line Depreciation Calculation: (Purchase Price of Asset – Approximate Salvage Value) ÷ Estimated Useful Life of Asset.