How do I check whether partitions on my SSD are properly aligned?

Parted has an align-check build in.

parted /dev/sda
align-check opt n

n is the partition you want to check.


Ensuring SSD alignment with parted tool looks like a pretty good guide for aligning your filesystem on the SSD:

  1. Get the block size of your SSD in bytes (there are heaps of tips, and I don't know which ones will work for which hardware).
  2. Start the partition editor:

    sudo parted
    
  3. Show the partition table:

    p
    
  4. Verify that the numbers in the Start and Size columns are divisible by the block size.

To be sure you have to use both built-in parted align-check option:

HDD:

DEVICE=/dev/sda && for i in `sudo parted $DEVICE print | grep -oE "^[[:blank:]]*[0-9]+"`; do   sudo parted $DEVICE align-check opt "$i"; done

SSD:

DEVICE=/dev/nvme0n1 && for i in `sudo parted $DEVICE print | grep -oE "^[[:blank:]]*[0-9]+"`; do   sudo parted $DEVICE align-check opt "$i"; done

and manual check (calculate divisibility by 4096B)

I've written a bash script to perform both checks:

https://github.com/crysman/check-partitions-alignment

(works on any GNU/Linux OS)

Or you can check manually using this table:

https://docs.google.com/spreadsheets/d/1dnDlhglxxgApvtUv0-nxn1iFYTqkjRELqCOWJtp3hbs/edit#gid=0

And yes, SSD HDD's partitions need to be aligned properly for maximum performance.