SSDs trim or not trim?

[Mark Kaine]

Seems almost controversial i see people saying they never do it, others probably do it daily... i do it every 2-3 weeks...

BUT shouldn't most SSDs actually have auto-trim built-in?  i know Samsung advertises that feature since forever... how does it actually work?

 

So what's the consensus, trim or nah?

[PDifolco]

I do it on a schedule because.. well because reasons

Can't see any harm in doing it

[mariushm]

You don't have to do it that often ... do it maybe once a month or once every two months... if you do it at all. 

 

The ssd controller should do its own garbage collection and maintenance when the drive is idle (not reading or writing files)

 

Trim basically forces the controller to determine which blocks of flash memory can be erased and made ready to write new data into the flash memory cells.  If you have lots of free space on the SSD, you will have lots of empty flash blocks that are ready to write data into, so there's no need to rush erasing of those flash blocks and wear them out faster. 

 

Think of the flash memory on your drive as arranged in blocks of 24/32/64 MB of flash memory, and each of these blocks has a bunch of "pages" that are 4096 bytes or some other size - so you have let's say 6000-1000 pages of 4K pages.   The controller can write data into an empty page (one of these 4096 byte sections), but can't overwrite these.  To make these 4096 chunks writable again, the whole block of 24/32/64 MB needs to be erased (and this process causes wear on the flash memory block, you have a limited number of erases). 

So every time you want to overwrite something or erase some files on the drive, the data remains on the drive and the new data (if you want to overwrite a block) is written into an empty page, in some other random block. 

 

The controller keeps track of stuff for each block ... ex this block has been erased 105 times, there's 1000 out of 6000 writable pages, 2000 pages with valid content, and 3000 pages that are ready to be reused. .... so 50% of the block contains unusable pages. 

If this block was to be erased, the ssd controller has to find blocks and writable pages for those 2000 pages with valid content and copy them in those other blocks, then erase the block, and now the controller has 6000 new pages that are writable and added to the pool of writable pages.

 

Trim forces the controller to build a list of all the blocks that should be erased if there needs to be more space freed (for example you may have a block with 90% outdated pages, but 500 erases and one block with 70% outdated pages and only 300 erases ... the controller may put this second block as higher priority for erasure. 

 

 

 

[will0hlep]

My conclusion has always been that it probably dosn't matter either way

[kokosnh]

If you don’t trim the performance will degrade, as ssd will have less nand blocks to write data to. So yes do trim, the default is 2 or 3 weeks, as if you do trim, all the deleted data says goodbye and you can’t recover it. 
 

The write amplification for doing it daily is marginal, the bigger problem is that you can’t recover the data ( well you can have daily backups, but not all people do them)

[ChrisLoudon]

38 minutes ago, Mark Kaine said:

So what's the consensus, trim or nah?

For general day-to-day use then no as the controller will do it automatically as part of its 'garbage collection' schedule.

 

The only reason to perform a manual trim would be if the drive was a 'storage-only' drive and was frequently filled and emptied. I have no idea on how frequently an SSD controller performs its garbage collection cycle or how its triggered but if it was once per week and you filled and emptied the drive more often than that then you'd see a big performance hit.

 

I suppose if the drive was frequently at capacity (or near to it) and you were needing to delete stuff to make room then running a manual Trim could help but other than the above 2 scenarios then i'd say nah

[Poinkachu]

If you use Windows, it auto-trim drives every 1 week by default no ?

[Mark Kaine]

59 minutes ago, Poinkachu said:

If you use Windows, it auto-trim drives every 1 week by default no ?

nope.

 

even if you set it like that. sometimes its weeks, sometimes months... especially the none os drives

 

which is funny cause os drive needs it least, barely any writes on it lmao 

[kokosnh]

It will only trim, if you deleted stuff from it…

 

 

[porina]

When you delete a file the OS should notify the drive that area can be wiped. It is up to the drive when to actually do it. A manual TRIM can force that to happen, and might catch unused areas that got missed for whatever reason. In normal use, let Windows handle it. I only ever manually TRIM if I'm throwing a lot of data around over a short time.

[Mark Kaine]

42 minutes ago, porina said:

When you delete a file the OS should notify the drive that area can be wiped. It is up to the drive when to actually do it. A manual TRIM can force that to happen, and might catch unused areas that got missed for whatever reason. In normal use, let Windows handle it. I only ever manually TRIM if I'm throwing a lot of data around over a short time.

thats what i tend to do, but then i see my os drive (which i barely use at all, there's no updates or anything going on either) has been "trimmed" basically weekly, almost daily and my 3 other drives (that see tons of read/writes) 0 times in weeks...

 

sometimes its the other way around ¯\_(ツ)_/¯ 

 

 

i guess ill just turn automatic trimming off and do it every 1-2 months manually. 

 

 

the thing is it only takes seconds,  but *someone's* gotta do it. 

 

and yeah, im not convinced drives do it automatic,  they may be just as buggy and unreliable than windows "automatic" settings.   

 

 

edit: thats what windows is doing constantly... first two drives daily  - instead of weekly  - other two drives never (because 11 days is when i did it last time)

 

 

just windows being windows i guess,  turned it off now.

 

[Doobeedoo]

Windows should do it weekly I saw that lately it reported it does it. Though drives that are decent do ot on it's own if need be.

[kokosnh]

Windows delete lots of stuff, from page file, to updates, to event logs etc, and other things, like cache of web browsers etc, it’s all happening in the os drive in the background.

[Blue4130]

7 hours ago, Mark Kaine said:

thats what i tend to do, but then i see my os drive (which i barely use at all, there's no updates or anything going on either) has been "trimmed" basically weekly, almost daily and my 3 other drives (that see tons of read/writes) 0 times in weeks...

 

sometimes its the other way around ¯\_(ツ)_/¯ 

 

 

i guess ill just turn automatic trimming off and do it every 1-2 months manually. 

 

 

the thing is it only takes seconds,  but *someone's* gotta do it. 

 

and yeah, im not convinced drives do it automatic,  they may be just as buggy and unreliable than windows "automatic" settings.   

 

 

edit: thats what windows is doing constantly... first two drives daily  - instead of weekly  - other two drives never (because 11 days is when i did it last time)

 

 

 

just windows being windows i guess,  turned it off now.

 

Hmm, I've never had any issues with windows doing it automatically. It's always worked as intended.

[Godlygamer23]

10 hours ago, kokosnh said:

It will only trim, if you deleted stuff from it…

Deletion itself does not trigger TRIM. My understanding is that Windows determines if TRIM is required during its analysis, based on the scheduling set up by the user - my specific configuration(see below) seems to contradict my view though. It may perform optimizations based on predetermined figures for how often SSDs require TRIM to run. Additionally, different SSDs may have different rules, but I kinda doubt garbage collection is constantly being performed after each deletion. 

 

My own configuration:

Spoiler

I have definitely deleted data(as in emptying the recycle bin) within those 12 days off my OS drive, and yet that's when it says TRIM was last run on.

 

Critical information missing: Since W7, Windows does automatically issue commands to the SSD that areas are free and can be deleted if that feature is enabled. W7 and newer should automatically activate that feature.

Edited September 12 by Godlygamer23

[Mark Kaine]

9 hours ago, kokosnh said:

Windows delete lots of stuff, from page file, to updates, to event logs etc

no updates, event logs don't seem to get deleted, page file is absolutely minimal compared to the sometimes terabytes that get moved around on the none os drives regularly (mostly Shadowplay) 

 

I'll file this under bug now or something because yes the drives that see the most data movement are the ones that get trimmed the least, however, occasionally they would be so in the end it probably really doesn't matter.

 

 

 

this is how pagefile typically looks like on my machine it barely gets used, i also never run out of ram even with like 100 of yt videos open...  

 

[worstalentscout]

14 hours ago, mariushm said:

You don't have to do it that often ... do it maybe once a month or once every two months... if you do it at all. 

 

The ssd controller should do its own garbage collection and maintenance when the drive is idle (not reading or writing files)

 

Trim basically forces the controller to determine which blocks of flash memory can be erased and made ready to write new data into the flash memory cells.  If you have lots of free space on the SSD, you will have lots of empty flash blocks that are ready to write data into, so there's no need to rush erasing of those flash blocks and wear them out faster. 

 

Think of the flash memory on your drive as arranged in blocks of 24/32/64 MB of flash memory, and each of these blocks has a bunch of "pages" that are 4096 bytes or some other size - so you have let's say 6000-1000 pages of 4K pages.   The controller can write data into an empty page (one of these 4096 byte sections), but can't overwrite these.  To make these 4096 chunks writable again, the whole block of 24/32/64 MB needs to be erased (and this process causes wear on the flash memory block, you have a limited number of erases). 

So every time you want to overwrite something or erase some files on the drive, the data remains on the drive and the new data (if you want to overwrite a block) is written into an empty page, in some other random block. 

 

The controller keeps track of stuff for each block ... ex this block has been erased 105 times, there's 1000 out of 6000 writable pages, 2000 pages with valid content, and 3000 pages that are ready to be reused. .... so 50% of the block contains unusable pages. 

If this block was to be erased, the ssd controller has to find blocks and writable pages for those 2000 pages with valid content and copy them in those other blocks, then erase the block, and now the controller has 6000 new pages that are writable and added to the pool of writable pages.

 

Trim forces the controller to build a list of all the blocks that should be erased if there needs to be more space freed (for example you may have a block with 90% outdated pages, but 500 erases and one block with 70% outdated pages and only 300 erases ... the controller may put this second block as higher priority for erasure. 

 

 

 

 

what about external SSDs ?........i have 2 of them (same model) but one is detected as SSD (can be trimmed) but the other one detected as HDD......

[kokosnh]

10 hours ago, Godlygamer23 said:

Deletion itself does not trigger TRIM

Well yes, read my post one more time. 
if you don’t delete anything. There’s nothing to trim… 

[Mark Kaine]

41 minutes ago, kokosnh said:

Well yes, read my post one more time. 
if you don’t delete anything. There’s nothing to trim… 

 and yet it still does it "on schedule" lol...

 

already told you deletion has nothing to do with it.

 

 

[kokosnh]

14 minutes ago, Mark Kaine said:

 and yet it still does it "on schedule" lol...

 

already told you deletion has nothing to do with it.

 

 

Yes, but no.

if there’s no deleted stuff then there is nothing to trim. 
it could say it analyzed the file system, but just that. 

 

[NobleGamer]

On 9/11/2024 at 7:53 AM, kokosnh said:

If you don’t trim the performance will degrade, as ssd will have less nand blocks to write data to.

So to summarize before this post becomes multipage, the answer is yes TRIM should be done because performance. Windows will automatically analyze it every so often (default pictured earlier is once per week), and if analysis indicates the SSD would benefit, then it will request TRIM.

 

On 9/11/2024 at 7:24 AM, Mark Kaine said:

Seems almost controversial

For me its more like a big rabbit hole that can get really confusing to understand holistically, like when I tried to determine whether an enclosure on LTT supported TRIM, and then it brought up questions of garbage collection versus drive sleep.