i need to store a large amount of data - about 10 million entries of the format

unique hash (64 chars), value 1 (5 chars), value 2 (9 chars)

i will be reading and deleting (but not updating) this data in quick succession. for example, i might write 10 lines, then read 3 and delete 3 lines, before moving on to more writes and reads...

its a single threaded desktop program so reads are only initiated after writes and deletes have been completed. i would like to avoid using a database so that the data can be human-readable from the file system and so that people who download and use my program can see it and inspect it for themselves. i expect my users to be running a linux os and my program is written in python.

i have come up with three possible options for how to store this data:

option 1

put the data in a single file. since the hashes are unique i can arrange them in ascending order like an index so as to give log2 N read times. deleting and inserting will happen often and would slow the process down as N gets large.

option 2

use the unique hash as a file name and put the values inside this file. this would be my preferred option so long as there are no obvious performance drawbacks? i know some file systems slow down when a large number of files exist in a single directory. and i really can't make any assumptions about which file system the users of my program will be using. i need to choose a solution which is quick on all file systems.

option 3

use the unique hash to create a directory to store the values in. so for example, if a record has hash abcd then i would create dir base_dir/a/b/c/d/ and then place the values in a file under d. does this get around the file system performance issue issue? or is this just as bad as option 2 depending on the type of file system the user is running?

question

so really i'm just looking for help to decide which option to pick. also if you have any other options that are superior to the ones i have listed here i would like to hear them. maybe some database software like mysqli that sores data in human-readable text? that would be ideal really, but i imagine that most databases would use binary for efficiency...