The Funtoo Linux project has transitioned to "Hobby Mode" and this wiki is now read-only.
Solid State Drives (SSD)
This page aims to highlight SSD relevant options for commands commonly used during system setup/install.
Installation
This section is in need of updates.
Partitioning
This section is in need of updates.
The default alignment of 1MiB provides for proper SSD performance. For gdisk, ensure each partition starts at integer multiple of 2048 (sectors). If you change gdisk's default boundary then the default for other programs may change as a result.
Cryptsetup/LUKS
This section is in need of updates.
cryptsetup luksFormat --align-payload 2048 (default)
cryptsetup luksOpen --allow-discards
mdadm RAID
This section is in need of updates.
mdadm -c 512 Aligns chunksize to 512KB erase block size times 1 data disk (for raid1)
LVM
This section is in need of updates.
pvcreate --data-alignment 512 (equal to value given as chunksize) ?default? --data-alignment-offset (should not be needed for correctly aligned partitions)
vgcreate -s 4M (default)
Create Files System
This section is in need of updates.
mkfs.ext4 -b 4096 -E stride=128,stripe_width=128 (erase block size / 4096) (for raid1)
mkfs.xfs -b 4096 -d sunit=1024,swidth=1024 OR -d su=512K,sw=512K (for raid1)
Clearing SSD Memory Cells
This section is in need of updates.
WARNING
Avoid using dd command to overwrite data on SSD. The SSD controller has its own algorithms for allocating writes based on its internal topology. Trying to overwrite data the usual way (e.g. dd if=/dev/zero of=/dev/sda ) is not only futile but will reduce the remaining number of writes to the flash cells. To inform the controller that all data can be purged use hdparm --security-erase. [1]