Trim and noatime on internal Emmc storage?

[AlanP]

Hello,

do I need to enable Trim and noatime on internal Emmc storage ?

Have you got advices for this kind of hardware under Manjaro and Linux ?

Thanks.

[bogdancovaciu]

@AlanP

Trim and noatime

Hello,

noatime should be used on the /tmp tmpfs
For the root you should use / ext4 rw,relatime,data=ordered 0 1 and enable periodic trim
Anyway, have seen people having different opinions on this. Maybe safer to consult wiki and take an informed decision
https://wiki.archlinux.org/index.php/Solid_state_drive#Periodic_TRIM

[AlanP]

@bogdancovaciu: By default, noatime is set for the root partition in /etc/fstab file of Manjaro. Are you sure that relatime must be defined for root partition rather ‘noatime’ ?

Is Trim supported for EmmC ? I know Trim is supported for SSD but I don’t see anything for EmmC.

Regards.

[bogdancovaciu]

See some fstab details. For me, what i mentioned seems to be more reliable overall. You will see that defaults is more or less relatime , yet defaults,discard will do continuous trim, that personally i don’t think is ok, and noatime option fully disables writing file access times to the drive …
https://wiki.archlinux.org/index.php/Fstab#atime_options

[AlanP]

Ok, but why the Manjaro Team have defined noatime and not relatime by default in /etc/fstab ? When you make a new install of Manjaro, you can check, noatime is defined by default in /etc/fstab.

About the Trim option, I know that perodic choice is more suitable than daily choice. But what I really want to know is if the Trim is suitable for internal EMMC storage. EMMc storage is different than SSD
storage.

[bogdancovaciu]

An install that is designated to multitude of hardware setups, will always provide defaults that work for all types of hard drives. Is not a bad thing, yet you can change to suit your particular needs, or leave it like that.

@AlanP

EMMc storage is different than SSD
storage.

Let me quote some documentation:

An eMMC chip is essentially an SD card that is built as a BGA chip soldered to the main board. Just like SSD drives, eMMC chips have a built-in controller, although eMMC controllers are considerably simpler and slower compared to those used in SSD drives. As a result, while eMMC may employ much of the same techniques as SSD drives (namely, overprovisioning, remapping, trimming and background erase), they may not implement some other options (e.g. many security features such as DRAT or DZAT). Even if an eMMC controller implements background garbage collection, it is going to work much slower compared to SSD drives since there is only a single channel available that is used for all read and write operations. eMMC chips do not have the massive parallelism of SSD drives, and are much slower to read or write data.

Notably, eMMC standard correctly defines trimming of empty blocks. So what happens to trimmed blocks located on an eMMC chip? Similar to an SSD drive, they may or may not be mapped out of the addressable space at any given time. Unlike SSDs, the eMMC standard does not define either DRAT (definite read after trim) or DZAT (definite zeroes after trim), which leaves it to the eMMC manufacturer to define what exactly the storage controller returns when an attempt is made to read a trimmed data block.

Similar to SSD drives, eMMC chips may have an overprovisioned area that is non-addressable and inaccessible from the outside.

So, you can ask the manufacturer what they recommend for it. Leave the fstab as is since you installed Manjaro and from time to time run:
sudo fstrim -v /
and avoid only the discard option, if you decide to change fstab …

[AlanP]

@bogdancovaciu: I have always heard that ‘noatime’ is the best choice to avoid writes to SSD or other type storage media as much as possible. Otherwise, regarding the trim, can I use the command: ‘systemctl enable fstrim.timer’ instead of ‘sudo fstrim -v /’ to permanently activate the trim ?

[bogdancovaciu]

yes, to have the timer enabled you run the systemctl command and will run every 7 days.