Capacity Estimation and Planning

 1 Byte = 8 bits

1 byte = 1 ASCII character. 

2 bytes = 1 UTF-16

UTF-8

UTF-8 is based on 8-bit code units. Each character is encoded as 1 to 4 bytes.

2^32  = 4,294,967,296

1 KB = 1000 Bytes

1 MB = 1000 KB

1 GB = 1000 MB

1 TB = 1000 GB

1 PB = 1000TB 

1 Million = 1,000,0000 = 10^6

1 Billion = 1,000,000,000 = 10^9

1 Trillion = 1,000,000,000,000 = 10^12

Request Calculation per second

1 M req per day = 1 M req / 86400 seconds = 12 req per second

1.5 M req per day = 1.5 * (1 M req / 86400 seconds) = 18 req per second

10 M req per day = 10 M req / 86400 seconds = 120 req per second

1 B req per day = 1B req / 86400 seconds = 12000 req per second

Redis can handle 81000 req per second

Number of users
Twitter users = 300 million active monthly users

Youtube = 2 Billion active monthly users
Number of videos watched per day = 5 billion

Facebook users 3 billion users out of which 2 billion are daily active users

Pastebin users = 17 million

Bitly = 600 million bitly link created per month.

Name	Length
char	1 byte
short	2 bytes
int	4 bytes
long	4 bytes
float	4 bytes
double	8 bytes
long double	16 bytes Note that on AIX® and Linux® PPC a long double is 8 bytes.
pointer	4 bytes
ptrdiff_t	4 bytes
size_t	4 bytes
time_t	4 bytes
clock_t	4 bytes

Videos :