# Tiktok

## Func req

1. Upload / download
2. Streaming video

## NFR

1 billion users, 1 bill DAU

1bill videos viewed per day

10 bill videos uploaded per year

150 countries

**Success metrics**: time in app (avg hour per day)

1 video 10 sec \~ 1 MB

Uploads: 10^10 uploads / 365 \~ 30^6 uploads per day / 100\_000 seconds a day = 300 videos / second (so then approximately 1000 videos per second in peak). So 1000 videos / second \* 1 Mb (10Mbits) = 10Gbits ingress (this is not a lot)

Storage: 10^10 uploads \* 1Mb = 10PB videos per year (including replication, different formats) -> 100 PB per year (blob storage)

Storage: metadata of video 10^10 \* 1KB = 10TB per year (NoSql storage)

Views (downloads): 10^9 per day / 100\_000 seconds = 10\_000 videos per second -> 100Gbits egress

## Assumptions

## Video storage

We can store old videos in archive (slow and cheap storage)

### Geo distribution

Partitioning video data by region. \
CDN