Re: newfs TRIM flag device support
Mark Millard <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
[Only replying to lists I subscribe to.] On Feb 15, 2024, at 19:19, Ordinary Bit <[email protected]> wrote: > 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? 2 contrasting examples: Example 0: Optane NVMe media (PCIe card or U.2, for example) Optane has no need of TRIM and, so, never supports TRIM. Example 1: microsd card media usage A microsd card in the normal type of microsd card slot on Small Board Computers (normally) supports TRIM. Take the same card and put it in a USB reader/writer and use it via USB on the same system: no TRIM is supported by FreeBSD over USB. FYI: When the file system has TRIM enabled, FreeBSD put out a notice if TRIM will not actually be used in the actual context in use. > 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. === Mark Millard marklmi at yahoo.com