PostgreSQL I/O Scheduler Recommendation

From what I have read, throughput for CFQ seems to be a little faster than Deadline and Noop, though they all process information a little differently.

I found this blog post that goes pretty in depth in comparing these 3 and even benchmarks them:
https://blog.pgaddict.com/posts/postgresql-io-schedulers-cfq-noop-deadline

Hey, I seem to be unable to change the scheduler on my server, "echo {scheduler choice} > /sys/block/sda/queue/scheduler", as recommended by several forum and blog posts does not work.

Does anybody have any advice on how to set the scheduler on an Ubuntu linode instance?

You can change that in rescue mode, because the file is being used. Or you can change via grub bootloader