Re: newfs TRIM flag device support

On Friday, 16 February 2024 at 12:33, Kevin Oberman <rkoberman@gmail.com> wrote:

> On Thu, Feb 15, 2024 at 7:19 PM Ordinary Bit <ordinarybit@proton.me> wrote:
>
>> Hi,
>>
>> I'm reading the newfs manual https://man.freebsd.org/cgi/man.cgi?newfs(8) to be able to know about the TRIM flag. In the manual under -t parameter, it mentioned about "underlying device support", what exactly is this device? Is it the host (for example, Raspberry Pi SD/eMMC host reader) or the SD/eMMC card (controller) or both?
>>
>> -t
>>
>> Turn  on	the TRIM enable	flag.  If enabled, and if the underly-
>>	ing device supports the BIO_DELETE  command,  the  file	system
>>	will  send  a  delete request to	the underlying device for each
>>	freed block.  The trim enable flag is typically set for	flash-
>>	memory devices to reduce	write amplification which reduces wear
>>	on write-limited	flash-memory and often improves	long-term per-
>>	formance.   Thinly provisioned storage also benefits by return-
>>	ing unused blocks to the	global pool.
>>
>> BR,
>>
>> orbit

Hi!

> TRIM is for SSDs. It is tied to the drive, but the controller or system. I think Linux enables it automatically, but I'm not sure. In the context of the description above, the drive is the device.

Thanks for sharing! I checked here https://en.wikipedia.org/wiki/Trim_(computing)#SD/MMC which says that there is a similar functionality of ATA TRIM to MMC and SD which is the ERASE (CMD38), this make me curious about TRIM support available in the UFS/FFS. I have tried a while ago enabling TRIM in my SanDisk Ultra microSDXC 64GB and when mounted, it shows enabled in the tunefs. However, I am still thinking if it works when TRIM is enabled in the rootfs and used it as my boot media in the Raspberry Pi microSD card slot. Anyway, this is worth a try.

BR,
orbit

> --
>
> Kevin Oberman, Part time kid herder and retired Network Engineer
> E-mail: rkoberman@gmail.com
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