Creating index in large table

MySQL & MariaDB Other MySQL® Questions
1

Hi,

  1. I have table that contains 16 million records (16,186,288 ; MyISAM ; latin1_swedish_ci ; 2.8 GiB ), and i need to:
    [LIST=1]
    [*] delete one index and create an index on other column
    [/LIST]

Any ideas how long it can take…

2)I need to backup 43GB database. What is the best way to do it? Any scripts or tools. The database is all time alive. There are about 2 inserts per second.