诸如SSD的现代数据存储设备需要ATA接口的TRA命令，为此，基于Linux内核的OS在文件系统级别提供了两种控制方法：
- 丢弃 -作为安装文件系统的选项安装。允许Linux内核在文件系统报告后立即将TRIM命令发送到设备。
- fstrim-作为OS服务手动或按计划启动的实用程序，它从FS发送已删除块的列表，以在设备上清除它们。
要启用fstrim，足以fstrim.service在systemd中激活该服务，但是与其使用fstrim.timer将在每周一次的TRIM中启动的计时器来代替将在内存中挂起的服务，还不如将其激活。
服务激活示例：
systemctl enable fstrim.service && \
systemctl start fstrim.service && \
systemctl status fstrim.service
但是，如果您的文件系统位于LVM卷和LUKS中的LVM上，则这些措施还不够 , ,
首先要做的是确认SATA控制器处于AHCI模式而不是IDE，否则TRIM将无法工作：
sudo hdparm -I /dev/sda | grep TRIM
* Data Set Management TRIM supported (limit 8 blocks)
* Deterministic read ZEROs after TRIM
TRIM supported, SATA AHCI BIOS UEFI.
, discard :
- ( )
- —
/etc/fstab - cryptsetup —
/etc/crypttab - LVM —
/etc/lvm/lvm.conf - —
/boot/grub/grub.cfg
. Arch Linux , Linux.
discard EXT4
/etc/fstab discard defaults, . EXT4. , SATA - /etc/fstab.
discard EXT4. :
sudo tune2fs -o discard /dev/mapper/vg1-lvroot
sudo tune2fs -o discard /dev/mapper/vg1-lvhome
sudo tune2fs -o discard /dev/mapper/vg1-lvvar
tune2fs. /dev/mapper/vg1-lvroot , EXT4 LVM:
sudo tune2fs -l /dev/mapper/vg1-lvroot | grep options
discard fstab
SSD , discard /etc/fstab , EXT4, .
, discard swap :
UUID=e86ab458-341d-4f59-8344-0271d2c363e8 / ext4 rw,noatime,discard 0 0
UUID=44b31816-1193-4dc1-9f58-f70df2250e1a /var ext4 rw,noatime,discard 0 0
UUID=372bc9ae-b581-49a4-abed-ca9f3b67edb6 /home ext4 rw,noatime,discard 0 0
UUID=0BE5-60FB /boot/efi vfat rw,relatime,discard,...,errors=remount-ro 0 0
UUID=cf67ae1e-3a17-4e5e-ac58-ef23725d2359 none swap defaults,discard,pri=-2 0 0
discard LVM
/etc/lvm/lvm.conf issue_discards 1:
devices {
issue_discards = 1
}
, TRIM , TRIM , , lvremove, lvreduce ..
discard root-
, discard , ( , . .) , crypttab:
WARNING: This command can have a negative security impact because it can make filesystem-level operations visible on the physical device. For example, information leaking filesystem type, used space, etc. may be extractable from the physical device if the discarded blocks can be located later. If in doubt, do not use it.
, . , , , , , ? , ? ? :)
, "" LUKS. TRIM , cryptsetup' --allow-discards /etc/crypttab , , /etc/crypttab, root- .
initramfs, initramfs grub Linux.
allow-discards /etc/default/grub cryptdevice GRUB_CMDLINE_LINUX.
:
GRUB_CMDLINE_LINUX="cryptdevice=UUID=3c121aac-ead9-4d57-88be-c1199acf72f0:cryptlvm"
:
GRUB_CMDLINE_LINUX="cryptdevice=UUID=3c121aac-ead9-4d57-88be-c1199acf72f0:cryptlvm:allow-discards"
"" grub':
sudo grub-mkconfig -o /boot/grub/grub.cfg
, initramfs encrypt cryptsetup lvm2:
cat /etc/mkinitcpio.conf | grep ^HOOKS
HOOKS=(base udev autodetect keyboard keymap consolefont modconf block encrypt lvm2 resume filesystems)
grub .
discard
, /home LUKS. , discard /etc/crypttab /etc/fstab.
: man crypttab
TRIM
:
lsblk --discard
NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
sda 0 512B 2G 0
├─sda1 0 512B 2G 0
└─sda2 0 512B 2G 0
└─cryptlvm 0 0B 0B 0
├─vg1-lvroot 0 0B 0B 0
├─vg1-lvvar 0 0B 0B 0
├─vg1-lvswap 0 0B 0B 0
└─vg1-lvhome 0 0B 0B 0
DISC-GRAN (discard granularity) DISC-MAX (discard max bytes), TRIM .
TRIM:
sudo fstrim -v /
/: 7,4 GiB (7906193408 bytes) trimmed
, TRIM . TRIM :
lsblk --discard
NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
sda 0 512B 2G 0
├─sda1 0 512B 2G 0
└─sda2 0 512B 2G 0
└─cryptlvm 0 512B 2G 0
├─vg1-lvroot 0 512B 2G 0
├─vg1-lvvar 0 512B 2G 0
├─vg1-lvswap 0 512B 2G 0
└─vg1-lvhome 0 512B 2G 0
DISC-GRAN 512B SSD 512 bytes. TRIM , . :
sudo cryptsetup status cryptlvm
/dev/mapper/cryptlvm is active and is in use.
type: LUKS1
cipher: aes-xts-plain64
keysize: 512 bits
key location: dm-crypt
device: /dev/sda2
sector size: 512
offset: 4096 sectors
size: 487806976 sectors
mode: read/write
sudo hdparm -I /dev/sda | grep -i "sector size"
Logical Sector size: 512 bytes
Physical Sector size: 512 bytes
sudo smartctl -a /dev/sda | grep -i "sector size"
Sector Size: 512 bytes logical/physical
!
UPDATE 14.04.2020 14:20: . AAngstrom .
UPDATE 23.04.2020 22:00: , "" , . vitaliy2