SSD/NVMe Tweaks (TRIM/Discard): Difference between revisions

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You can run discard operations using different methods:
You can run discard operations using different methods:


* Batch discard: Are run explicitly by the user. They discard all unused blocks in the selected file systems.
* '''Batch discard''': Are run explicitly by the user. They discard all unused blocks in the selected file systems.
* Online discard: Are specified at mount time. They run in real time without user intervention. Online discard operations discard only the blocks that are transitioning from used to free.
* '''Online discard''': Are specified at mount time. They run in real time without user intervention. Online discard operations discard only the blocks that are transitioning from used to free.
* Periodic discard: Are batch operations that are run regularly by a <code>systemd</code> service.
* '''Periodic discard''': Are batch operations that are run regularly by a <code>systemd</code> service.


All types are supported by the XFS and ext4 file systems and by VDO.
All types are supported by the XFS and ext4 file systems and by VDO.


'''Recommendations.'''
'''Recommendations.''' Red Hat recommends that you '''use batch or periodic discard'''. Use online discard only if:
Red Hat recommends that you use batch or periodic discard.
 
Use online discard only if:


* the system’s workload is such that batch discard is not feasible, or
* the system’s workload is such that batch discard is not feasible, or
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qm agent 251 fstrim        # Where 251 is the Id of the container
qm agent 251 fstrim        # Where 251 is the Id of the container
</syntaxhighlight>
</syntaxhighlight>
*


== [Periodic Discard] Set the TRIM Job to Daily ==
== [Periodic Discard] Set the TRIM Job to Daily ==
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/dev/disk/by-uuid/09e7c8ed-fb55-4a44-8be4-18b1696fc714 / ext4 discard,async,noatime,nodiratime,errors=remount-ro 0 1
/dev/disk/by-uuid/09e7c8ed-fb55-4a44-8be4-18b1696fc714 / ext4 discard,async,noatime,nodiratime,errors=remount-ro 0 1


</syntaxhighlight>'''Warning:''' Users need to be certain that their '''SSD supports TRIM''' before attempting to use it. Data loss can occur otherwise!
</syntaxhighlight>'''Warning:''' Users need to be certain that their '''SSD supports TRIM''' before attempting to use it. Data loss can occur otherwise!  


==== test ====
To test whether the SSD device supports TRIM/Discard option you can use either of the following commands. <syntaxhighlight lang="shell" line="1">
To test whether the SSD device supports TRIM/Discard option you can use either of the following commands. <syntaxhighlight lang="shell" line="1">
sudo hdparm -I /dev/sda | grep TRIM
sudo hdparm -I /dev/sda | grep TRIM
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=== References ===
=== References ===
* Arch Linux Wiki: [https://wiki.archlinux.org/title/Solid_state_drive#Continuous_TRIM '''Solid state drive''']
* Arch Linux Wiki: [https://wiki.archlinux.org/title/Solid_state_drive#Continuous_TRIM '''Solid state drive''']
* Red Hat Documentation: [https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_storage_devices/discarding-unused-blocks_managing-storage-devices <u>Red Hat Enterprise Linux > '''8''' > Managing storage devices > Chapter 8. '''Discarding unused blocks'''</u>]
* How-To Geek: [https://www.howtogeek.com/62761/how-to-tweak-your-ssd-in-ubuntu-for-better-performance/ '''How to Tweak Your SSD in Ubuntu for Better Performance''']
* How-To Geek: [https://www.howtogeek.com/62761/how-to-tweak-your-ssd-in-ubuntu-for-better-performance/ '''How to Tweak Your SSD in Ubuntu for Better Performance''']
* How-To Geek: [https://www.howtogeek.com/howto/38125/htg-explains-what-is-the-linux-fstab-and-how-does-it-work/ '''What Is the Linux fstab File, and How Does It Work?''']
* How-To Geek: [https://www.howtogeek.com/howto/38125/htg-explains-what-is-the-linux-fstab-and-how-does-it-work/ '''What Is the Linux fstab File, and How Does It Work?''']

Revision as of 10:42, 18 August 2022

Lin­ux Desk­top
Lin­ux Serv­er

Note, with­in the ex­am­ples in the fol­low­ing sec­tions, /​​​dev/​​​sda refers to a SSD de­vice while /​​​dev/​​​nvme0n1 refers to a NVMe de­vice.

Dis­card­ing Un­used Blocks

You can per­form or sched­ule dis­card op­er­a­tions on block de­vices that sup­port them. Block dis­card op­er­a­tions dis­card blocks that are no longer in use by a mount­ed file sys­tem. They are use­ful on:

  • Sol­id-state dri­ves (SS­Ds)
  • Thin­ly-pro­vi­sioned stor­age

You can run dis­card op­er­a­tions us­ing dif­fer­ent meth­ods:

  • Batch dis­card: Are run ex­plic­it­ly by the user. They dis­card all un­used blocks in the se­lect­ed file sys­tems.
  • On­line dis­card: Are spec­i­fied at mount time. They run in re­al time with­out user in­ter­ven­tion. On­line dis­card op­er­a­tions dis­card on­ly the blocks that are tran­si­tion­ing from used to free.
  • Pe­ri­od­ic dis­card: Are batch op­er­a­tions that are run reg­u­lar­ly by a sys­temd ser­vice.

All types are sup­port­ed by the XFS and ext4 file sys­tems and by VDO.

Rec­om­men­da­tions. Red Hat rec­om­mends that you use batch or pe­ri­od­ic dis­card. Use on­line dis­card on­ly if:

  • the system’s work­load is such that batch dis­card is not fea­si­ble, or
  • on­line dis­card op­er­a­tions are nec­es­sary to main­tain per­for­mance.

Ref­er­ences

Get Full SSD/​​​NVMe/​​​HDD De­vice In­fo

For SSD/HDD de­vices use: 

smartctl -x /dev/sda            # -x, --xall; -a, --all

hdparm -I /dev/sda              # doesn't support NVMe

For NVMe de­vices use: 

smartctl -x /dev/nvme0n1        # -x, --xall; -a, --all

nvme smart-log -H /dev/nvme0n1  # apt install nvme-cli

Ref­er­ences

[Batch dis­card] TRIM from CLI

fstrim com­mand

sudo fstrim -av             # trim/discardd all mounted devices, verbose output
sudo fstrim -v /            # trim/discardd the root fs, verbose output
sudo fstrim /mount-point    # trim/discardd a device mounted at specific mount point

Prox­moxVE Node

For unpriv­i­leged Lin­ux con­tain­ers use the fol­low­ing com­mand at the Prox­moxVE host side .

pct fstrim 151              # Where 151 is the Id of the container

For priv­i­leged con­tain­ers fstrim could be ex­e­cut­ed al­so from the guest's side. For the vir­tu­al ma­chines – en­able the dis­card and SSD em­u­la­tion op­tions in the stor­age de­vice con­fig­u­ra­tion, use Vir­tIo SC­SI as con­troller and trim at the guest side. Al­so we can use one of the fol­low­ing com­mands at he Prox­moxVE host side.

qm guest cmd 251 fstrim     # Where 251 is the Id of the container

qm agent 251 fstrim         # Where 251 is the Id of the container

[Pe­ri­od­ic Dis­card] Set the TRIM Job to Dai­ly

sudo systemctl enable fstrim.timer

sudo mkdir /etc/systemd/system/fstrim.timer.d
sudo nano /etc/systemd/system/fstrim.timer.d/override.conf

[Timer]
OnCalendar=
OnCalendar=daily

Re­boot the sys­tem or do dae­mon-re­load and check the up­dat­ed val­ue.

sudo systemctl daemon-reload

systemctl cat fstrim.timer

# /lib/systemd/system/fstrim.timer
[Unit]
Description=Discard unused blocks once a week
Documentation=man:fstrim
ConditionVirtualization=!container

[Timer]
OnCalendar=weekly
AccuracySec=1h
Persistent=true

[Install]
WantedBy=timers.target

# /etc/systemd/system/fstrim.timer.d/override.conf
[Timer]
OnCalendar=
OnCalendar=daily

sudo systemctl status fstrim.service
sudo systemctl status fstrim.timer

Un­do the change if you need.

sudo rm -v /etc/systemd/system/fstrim.timer.d/override.conf

Ref­er­ences

[On­line Dis­card] En­able TRIM in /​​​etc/​​​fstab

This ap­proach is not rec­om­mend­ed by the most man­u­als.

sudo nano /etc/fstab

#/dev/disk/by-uuid/09e7c8ed-fb55-4a44-8be4-18b1696fc714 / ext4 defaults 0 0
/dev/disk/by-uuid/09e7c8ed-fb55-4a44-8be4-18b1696fc714 / ext4 discard,async,noatime,nodiratime,errors=remount-ro 0 1

Warn­ing: Users need to be cer­tain that their SSD sup­ports TRIM be­fore at­tempt­ing to use it. Da­ta loss can oc­cur oth­er­wise!

test

To test whether the SSD de­vice sup­ports TRIM/​​​Discard op­tion you can use ei­ther of the fol­low­ing com­mands. 

sudo hdparm -I /dev/sda | grep TRIM

* Data Set Management TRIM supported (limit 8 blocks)

sudo smartctl --all /dev/sda | grep TRIM

TRIM Command:     Available

To test does an NVMe sup­ports TRIM (phys­i­cal dis­card op­tion) the out­put of the fol­low­ing com­mand must be greater than 0. This ap­proach is ap­plic­a­ble al­so for SSD de­vices.

cat /sys/block/nvme0n1/queue/discard_max_bytes

cat /sys/block/sda/queue/discard_max_bytes

Ref­er­ences

Tweak the AMP val­ue of SSD

Most Lin­ux dis­tri­b­u­tions use Lin­ux Kernel’s “Ad­vanced Pow­er Man­age­ment (APM)” API to han­dle con­fig­u­ra­tion, op­ti­mize per­for­mance, and en­sure sta­bil­i­ty of stor­age de­vices. These de­vices are as­signed an APM val­ue be­tween 1 and 255 to con­trol their pow­er man­age­ment thresh­olds. A val­ue of 254 in­di­cates best per­for­mance, while a val­ue of 1 in­di­cates bet­ter pow­er man­age­ment. As­sign­ing a val­ue of 255 will dis­able APM al­to­geth­er. By de­fault, SS­Ds are as­signed an APM of 254 when the sys­tem is run­ning on ex­ter­nal pow­er. In bat­tery mode, the APM lev­el is set to 128, re­duc­ing the read and write speeds of SS­Ds. This ar­ti­cle ex­plains how to in­crease SSD APM lev­els to 254 when your Lin­ux lap­top is run­ning on bat­tery mode. 

sudo hdparm -B254 /dev/sda

Get the cur­rent AMP val­ue.

sudo hdparm -B /dev/sda

Test the per­for­mance. 

sudo hdparm -tT /dev/sda

Ref­er­ences

See al­so


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