My optimizations for /var/log and /tmp/large

fstab-part-largetmp

/dev/mapper/largetmp1                                           /tmp/large              ext4    noauto,nosuid,noatime,delalloc,nobarrier,data=writeback,commit=36000    0       0

fstab-part-log

# There is a non-critial partition where /var/log is stored. When there aren't much data to be written, it simply waits up to one hour.
# This is aimed to reduce SSD write amplification. I hope it works correctly. I haven't verified it.
UUID=someeee-long-long-long-uuuuuuiiiddd       /non-critical   ext4    nosuid,noatime,commit=3600      0               2

mount-largetmp

#!/bin/bash
DEV=/dev/mapper/largetmp1
(
	sudo mkfs.ext4 "$DEV" -E lazy_itable_init -m 0 -O sparse_super &&
	sudo tune2fs -o journal_data_writeback "$DEV" &&
	sudo tune2fs -O ^has_journal "$DEV" &&
	sudo mkdir -p /tmp/large &&
	sudo mount /tmp/large &&
	sudo chmod 1777 /tmp/large
) || exit 2

var-log

% # I use symlink. It may be an suboptimal approach, I had some issues with AppArmor.
% # Since the /var/log is the only thing moved to /non/critical, I could have created a partition for /var/log.
% ll /var/log  
lrwxrwxrwx 1 root root 22 Apr  4 22:21 /var/log -> /non-critical//var/log/

Very nice trick, I am planning to use it in my RaspberryPI2