Petabyte to Exabit

1 petabyte (PB) = 1,000 terabytes (TB) in the SI decimal system. In the binary IEC system, 1 pebibyte (PiB) = 1,024 tebibytes (TiB) = 1,125,899,906,842,624 bytes. The distinction matters for enterprise storage procurement: a petabyte of raw disk capacity appears as about 909 TiB in an OS reporting binary units.

Petabyte-scale storage is common at: social media platforms (Facebook/Meta stores over 100 PB of photos alone), streaming services (Netflix's content library is estimated at 100+ PB), government agencies (US NSA, CERN particle physics data), genomic research institutions, and large financial exchanges storing tick-level trading data. Major cloud providers (AWS, Azure, GCP) collectively store zettabytes.

In 2024, cloud storage costs roughly $20–25 per TB per month (S3 standard tier), making 1 PB approximately $20,000–$25,000/month. Raw enterprise disk hardware for 1 PB runs about $20,000–$50,000 upfront (at $20–50 per TB for high-density drives), plus ongoing power, cooling, and management overhead. Tape-based archival storage is considerably cheaper at $2–5 per TB.

YouTube users upload approximately 500 hours of video per minute, or 720,000 hours per day. At an average compressed size of 1–2 GB per hour of HD video, that equates to roughly 720–1,440 TB (0.7–1.4 PB) of new video data per day — before YouTube re-encodes into multiple formats and quality levels, which multiplies storage requirements several-fold.

The SI prefix hierarchy above petabyte: exabyte (EB, 10¹⁸ bytes), zettabyte (ZB, 10²¹ bytes), yottabyte (YB, 10²⁴ bytes), ronnabyte (RB, 10²⁷ bytes), and quettabyte (QB, 10³⁰ bytes) — the last two added by the BIPM in 2022. Current global data storage is estimated in the hundreds of exabytes; no single organisation approaches yottabyte scale.

One exabit = 10¹⁸ bits = 125,000 terabytes = 125 petabytes. If every person on Earth (8 billion people) each stored 15 GB of data — roughly a modern smartphone's photos and messages — the total would be about 120 exabytes, or about 960 exabits. The entire human genome is about 1.5 GB; sequencing every person on Earth would produce about 12 exabytes of data.

Cisco's annual internet traffic reports estimated global IP traffic at roughly 4.8 exabytes per day in 2022, rising about 20% per year. Expressed in bits, that's about 38 exabits per day or roughly 440 petabits per second continuously. Video streaming accounts for over 60% of total internet traffic volume.

Data gravity is the principle that massive datasets attract applications, services, and additional data toward them — rather than being moved to where processing occurs. At exabit scale, physically transferring data becomes impractical: moving 1 exabit over a 100 Gbps link takes 116 days. Instead, companies deploy compute resources alongside the data. This effect drives cloud concentration — once an organisation stores exabits in AWS or Azure, the cost and latency of moving that data elsewhere creates powerful vendor lock-in, shaping the economics of the entire cloud industry.

The Square Kilometer Array (SKA), under construction in Australia and South Africa, will be the world's largest radio telescope. Its thousands of antennas will collectively produce roughly 1 exabit of raw sensor data per day — more than the entire global internet traffic of the early 2000s. This data cannot be stored in full; instead, on-site supercomputers reduce it by a factor of ~10,000 in real time, keeping only scientifically relevant signals. The SKA illustrates how radio astronomy pushes data processing to extreme scales that rival commercial internet infrastructure.

At 1 Gbps (a fast home connection), downloading 1 exabit would take 1 billion seconds — about 31.7 years. At 1 Tbps (a high-end data center link), it would take 1 million seconds, or about 11.6 days. This illustrates why exabit-scale data movements require massively parallel infrastructure — no single link or device handles exabit transfers directly.