Linux Gzip increasing size

Question

I try to gzip a file abc.log which has size of 111 bytes, but after gzip, the size of the file increased to 125 bytes, why is that? Is it when i perform gzip, it will create header and trailer that has certain size?

Command used:

gzip -5 abc.log

Answer 1

Not just gzip, but attempting to compress a file which is already as small as possible can increase the size (because each method for compression has some overhead in the form of header, tables, etc). This is also referred to as negative compression.

Further reading

• What's the most that GZIP or DEFLATE can increase a file size?
• Why GZip compression increases the file size for some extension?
• Optimizing encoding and transfer size of text-based assets