USEFULL NOTES ABOUT SSD DISKS

- avoid TLC NAND based ssd if you plan to have a lot of writes (40-50Gb/day)

- add 'noatime' o 'relatime' to avoid unnecessary writes (kusa default already
  have this, but you must manually add this option for partitions created
  outside kusa control)

- DO NOT USE "discard" option in /etc/fstab for ext4, can have bad impact on
  performances and some ssd doesn't like it

IMPORTANT!

- with newer and/or decent ssd, that are overprovisioned, there NO NEED to
  activate or call trim


I/O SCHEDULER

- for SCSI/SATA ssd, that use regulard IO-scheduler (NMVe uses it's own driver
  and scheduler), change the behaviour in "deadline"; default scheduler queues
  up data for writing, to optimize heads seeks, but ssd doesn't have heads

  	echo "deadline" > /sys/block/sdX/queue/scheduler


LVM/CRYPT

- set "issue_discards = 1" in /etc/lvm/lvm.conf (usefull for non-ssd disks,
  at least does nothing)

- set "discard" option in /etc/cryptab for dm-crypt

	Example for dm-crypt's /etc/crypttab:

	#<target name>    <source device>            <key file>  <options>
	var  UUID=01234567-89ab-cdef-0123-456789abcdef  none  luks,discard

