About StorageMath.org
Subash Geetha Krishnan
Technical Lead - Nimble Storage at HPE Services Storage Support
Based in Singapore
Subash Geetha Krishnan is a Tech Lead for Nimble Storage at HPE Services Storage Support in Singapore, with 15+ years in enterprise storage across EMC, Dell, HPE, IBM, NetApp and Pure Storage. He created StorageMath.org, a free set of data unit converters and storage calculators, and EOSL.date, which tracks end-of-life dates for enterprise hardware and software. Outside work, he invests and trades in Indian markets and open-sources algorithmic trading strategies for education.
What is StorageMath.org?
StorageMath.org is a free, simple, and fast set of online calculators and converters built for storage professionals, system administrators, and IT engineers. Whether you're converting data units, calculating RAID capacity and overhead, estimating data transfer times, or planning storage capacity for your next project, it has you covered.
No ads cluttering your screen. No complex interfaces. Just straightforward calculations that work, and every one runs in your browser.
Why I Built This
After 15+ years of working with enterprise storage across EMC, Dell, HPE, IBM, NetApp, and Pure Storage platforms, one frustration kept coming back: doing quick storage math shouldn't require a spreadsheet, a calculator app, and three browser tabs.
Here's what a typical day looked like:
- Customer asks: "How long will it take to migrate 50 TB over a 10 Gbps link?" I'd open a calculator, convert units, account for overhead, and hope I didn't mess up the decimal places.
- Capacity planning meeting: "What's the usable capacity of a RAID 6 configuration with 12 x 4 TB drives?" More mental math, more chances for errors.
- Quick Slack message: "Is 1 TiB the same as 1 TB?" Explaining binary vs decimal units for the hundredth time.
- Migration planning: "We have a 2-hour maintenance window. How much data can we realistically move?" Back to the calculator.
I've dealt with these calculations thousands of times: during late-night troubleshooting calls, in customer meetings, while designing SAN architectures, and when planning multi-petabyte migrations. Every time, I wished there was a single, reliable tool that understood storage the way storage engineers think.
So I built one.
Why Trust These Calculations?
This isn't a generic calculator built by someone who Googled "how does RAID work." It's built by someone who has:
- Worked hands-on with EMC Symmetrix, VMAX, VNX, VPLEX, Unity
- Managed HP 3PAR, HPE Nimble (Hybrid Flash, All Flash, dHCI), Primera, Alletra
- Supported IBM DS8000, FlashSystem, Storwize V7000 series
- Administered NetApp AFF A800/A700, FAS series
- Configured countless Brocade FC switches, zoning, ISL configurations
- Designed and executed multi-petabyte migrations with zero data loss
- Worked with customers across banking, consulting, and technology sectors
The full list of degrees and certifications is further down this page.
Professional profile
Enterprise storage, day to day
Subash is a Tech Lead for Nimble Storage at HPE Services Storage Support, based in Singapore, with more than 15 years in enterprise storage across EMC, Dell, HPE, IBM, NetApp and Pure Storage. Hands-on experience spans EMC Symmetrix and VMAX, HP 3PAR and NetApp AFF systems, including multi-petabyte migrations completed with zero data loss.
Credentials include a Specialist Diploma in Cyber Security Management from Singapore Polytechnic (2021), Dell EMC specialist certifications in VNX and VPLEX, an MSc in Computer Science and a BCA from Bharathiar University. The full list is under Education and training below.
That background led to two free tools. EOSL.date tracks end-of-sale, end-of-life and end-of-support dates for hardware from vendors such as Cisco, Dell EMC, HPE, IBM, NetApp and Pure Storage. StorageMath.org is a set of calculators for storage professionals, covering RAID, IOPS, capacity planning, transfer time, and deduplication and compression.
Subash also writes technical tutorials for the HPE developer community. HPE GreenLake API – how to fetch and analyze audit logs in Python (July 2024) shows how to authenticate with OAuth2, pull audit logs from the API and export them to Excel for analysis and compliance records.
Markets, trading and investing
Subash has been active in the Indian stock market since 2008, and the route there was gradual: first trading on broker calls, then learning to trade manually, and eventually writing code to do it. The 2020 COVID crash was painful to watch, and the response was to invest more through it rather than sell.
In parallel, Subash began trading algorithmically through broker APIs, starting with Zerodha’s Kite Connect (this Economic Times report covers Zerodha opening it to fintech developers) and later Finvasia’s Shoonya API. It is a side pursuit that runs alongside a full-time engineering career.
The strategies are open source. algo_trading_strategies_india on GitHub collects Python strategies for Indian markets across stocks, futures and options, including index option selling and buying, short selling and indicator-based approaches, with a focus on index option selling, together with broker utilities such as auto-login and historical data collection. It is shared for education only.
The full story is in this Substack article, and Subash answers trading questions on the TradingQnA forum.
Videos
- A FIN NIFTY short strangle strategy for expiry day
- Tracking a Nifty Financial Services (FIN NIFTY) portfolio on Google Finance
- The Finvasia technical glitch of 13 April 2023
- Saurabh Mukherjea on the power of reading
- Prostocks trading account review, from an NRI trader’s view
Not investment advice. Trading and investing carry risk, and studies by India’s market regulator, SEBI, have found that most individual traders in equity derivatives lose money. Subash’s experience and open-source strategies are shared for education, not as recommendations.
Education and certifications
| Credential | Awarded by | Year |
|---|---|---|
| Specialist Diploma in Cyber Security Management | Singapore Polytechnic, Singapore | 2021 |
| Certificate in Infocomm Security & Defences | Singapore Polytechnic, Singapore | 2021 |
| Certificate in Security Incident Management | Singapore Polytechnic, Singapore | 2021 |
| Master of Science (MSc) in Computer Science | Bharathiar University, Coimbatore, India | 2016 |
| Bachelor of Computer Applications (BCA) | Bharathiar University, Coimbatore, India | 2009 |
| Specialist - Implementation Engineer, VPLEX Version 1.0 | Dell EMC | 2015 |
| ViPR SRM 3.x Storage Resource Management | Dell EMC | 2015 |
| Specialist - Implementation Engineer, VNX Solutions Version 8.0 | Dell EMC | 2014 |
| Specialist - Systems Administrator, VNX Solutions Version 8.0 | Dell EMC | 2014 |
| VNX Unified Storage Management (instructor-led training) | Dell EMC | 2014 |
| Associate - Cloud Infrastructure and Services Version 1.0 | Dell EMC | 2014 |
| Associate - Information Storage and Management Version 2.0 | Dell EMC | 2013 |
| SAN Management (instructor-led training) | Dell EMC | 2012 |
| Cisco Certified Network Associate (CCNA), expired 2014 | Cisco | 2011 |
| Microsoft Certified Systems Administrator (MCSA) on Windows Server 2003 | Microsoft | — |
| Higher Secondary Examination (Class XII, Science) | Board of Higher Secondary Examination, Government of Kerala, Thiruvananthapuram, India | 2006 |
| Secondary School Examination (Class X) | Central Board of Secondary Education (CBSE), Delhi, India | 2003 |
Areas of expertise
The topics behind the converters and calculators on this site, from data units and RAID maths to the enterprise arrays and SAN fabrics they are used on.
Data units and conversion
- Data storage units
- Data unit conversion
- Bits and bytes
- Kilobyte, megabyte, gigabyte, terabyte and petabyte
- Kibibyte, mebibyte, gibibyte and tebibyte
- Exabyte, zettabyte and yottabyte
- Decimal (SI) vs binary (IEC) prefixes
- TB vs TiB
- GB vs GiB
- 1000 vs 1024 conversion
- Data transfer rate units
- Bits per second (bps, Kbps, Mbps, Gbps)
- Mbps vs MB/s
- Bandwidth and data rate conversion
- Storage unit conversion tables
- Why a 1 TB drive shows less capacity
Storage capacity and planning
- Storage capacity planning
- Storage sizing
- Raw vs usable capacity
- Effective capacity
- Formatted capacity
- RAID overhead
- Hot spares
- Thin provisioning
RAID and file systems
- RAID levels
- RAID configuration
- RAID 0
- RAID 1
- RAID 5
- RAID 6
- RAID 10
- RAID 50
- RAID 60
- Striping, mirroring and parity
- Fault tolerance
- RAID rebuild time
- Unrecoverable read error (URE)
- ZFS RAIDZ
- BTRFS RAID
Performance and throughput
- Storage performance
- IOPS
- Throughput (MB/s)
- Latency
- Queue depth
- Little's Law
- Random vs sequential I/O
- Block size
- Read/write ratio
Data efficiency
- Deduplication
- Compression
- Data reduction ratio
- Space savings
Backup, migration and transfer
- Backup capacity planning
- GFS backup retention
- Backup and recovery
- Data protection
- Data migration
- Multi-petabyte migration
- Data transfer time
- Migration window planning
Flash, NVMe and PCIe
- Flash storage
- NVMe
- NVMe queue depth
- PCIe bandwidth (Gen 3, 4, 5 and 6)
- SSD endurance
- SSD lifespan
- DWPD (drive writes per day)
- TBW (terabytes written)
Cost and cloud storage
- Storage cost per TB
- RAID price per TB
- Cloud storage pricing
- Amazon S3
- Azure Blob Storage
- Google Cloud Storage
- Storage tiering
Enterprise storage platforms
- Enterprise storage
- EMC Symmetrix
- EMC VMAX
- EMC VNX
- EMC VPLEX
- Dell EMC Unity
- HPE Nimble Storage
- HP 3PAR
- HPE Primera
- HPE Alletra
- IBM DS8000
- IBM FlashSystem
- IBM Storwize
- NetApp AFF and FAS
- Pure Storage
- HPE GreenLake API
SAN, networking and security
- SAN architecture
- SAN management
- Storage area networks
- Fibre Channel
- Brocade Fibre Channel zoning
- ISL configuration
- iSCSI
- Network fundamentals (CCNA)
- Cyber security management
Let's connect
Have suggestions for new calculators? Found a bug? Want to discuss storage architecture? I'd love to hear from you: email [email protected], or use the contact page.
| Platform | Profile |
|---|---|
| GitHub | github.com/buzzsubash |
| linkedin.com/in/buzzsubash | |
| Substack | buzzsubash.substack.com |
| TradingQnA | tradingqna.com/u/buzzsubash/summary |
| X | x.com/buzzsubash |
| facebook.com/buzzsubash | |
| reddit.com/user/buzzsubash | |
| HPE Community | community.hpe.com/t5/user/viewprofilepage/user-id/2170290 |
| in.pinterest.com/buzzsubash | |
| instagram.com/buzzsubash | |
| YouTube | youtube.com/channel/UCZrxOLPkc_MZVL_-z_P7QOg |
| TikTok | tiktok.com/@buzzsubash |
| Behance | behance.net/buzzsubash |
| Quora | quora.com/profile/Subash-Krishnan-20 |
| Kaggle | kaggle.com/subashkrishnan |
| Credly | credly.com/users/subash-krishnan |
| Blog | EMC SAN Info |
A Note on Accuracy
StorageMath.org provides calculations based on standard formulas and industry conventions. While I've built these calculators based on real-world experience, please note:
- Actual usable capacity may vary based on vendor implementation, file system overhead, and metadata requirements
- Transfer times are theoretical maximums; real-world performance depends on network conditions, protocol overhead, and system load
- Always verify critical calculations with your vendor documentation and conduct proper testing before production implementations
This tool is meant to help you get quick estimates and sanity-check your numbers, not replace proper capacity planning and vendor consultation.