SSD alignment on linux with ext4 and LVM

First make sure to create partitions aligned to your SSD erase block size (in my case 512k):
sudo fdisk -H32 -S32 /dev/sdb
You can check with fdisk -lu /dev/sdb that the start of each partition is divisible by 512.

Then initialize the desired partition to use with LVM2 using the dataalignment parameter:
pvcreate --dataalignment 512k /dev/sdb1
Make sure your /etc/lvm/lvm.conf contains the following options:

    md_chunk_alignment = 1
    data_alignment_detection = 1
    data_alignment = 0
    data_alignment_offset_detection = 1

Now you can use vgcreate to create your volume grup, and then lvcreate to create the logical volumes.

When creating ext4 filesystems (with TRIM support), use the following command:
mkfs.ext4 -O extent -b 4096 -E stride=128,stripe-width=128 /dev/mapper/vg1-test
stride and stripe-width are calculated as sector size / block size = 512k / 4k = 128

When mounting ext4 filesystems, use the ‘discard‘ parameter to enable TRIM support:
mount -o discard,noatime,nodiratime /dev/mapper/vg1-test /mnt/

Extra tip: for more speed you can consider turning off journaling (to avoid double-write overhead), at the cost of an easily corruptable filesystem.
Check if journaling is enabled: dumpe2fs /dev/mapper/vg1-test |grep 'Filesystem features'
Disable journaling: tune2fs -O ^has_journal