Why is gsutil -m cp -R much faster than gsutil cp -R

google-compute-engine, gsutil

Solution

From the documentation of `gsutil cp`:

If you have a large number of files to upload you might want to use the `gsutil -m` option, to perform a parallel (multi-threaded/multi-processing) copy:

`gsutil -m cp -R dir gs://my_bucket'`

So the reason is that the `-m` flag makes the `cp` command open multiple simultaneous requests to copy the files in parallel, therefore speeding up considerably.

Problem

Hi all I am using GCE and now I'm new to bucket. I have tons of pics on my other bucket. I tried copying it as ``` sudo gsutil cp -R dir dir ``` it took me 30 mins still didn't finished the file copy so I tried the suggestion which is to use the -m command ``` sudo gsutil -m cp -R dir dir ``` it was a lot faster. But I wonder what makes it faster. and what does -m stand for? Thanks!

Original source