External SSD drives without Trim support

dimme

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I have a few external SSD drives is a USB3.1 and 3.0 cases. They are Samsung 850 & 860 EVO drives. I store my photo collection and working files on these and they are backed up. Do i need to be concerned because TRIM is not supported on these drives. What are the "side effects" of not having trim support.
 

Weaselboy

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No TRIM results in a little more wear on the drive, but these things last about forever anyway, so I would worry too much about it.

No TRIM can also over time lead to slower write speeds, but again, lots of people use these drives without TRIM and don't see the slowdowns.

So while TRIM is a good thing and should IMO be enabled when possible, not having it likely will not cause a problem. Even if it does and the drive slows some, it will still work.
 
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dimme

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No TRIM results in a little more wear on the drive, but these things last about forever anyway, so I would worry too much about it.

No TRIM can also over time lead to slower write speeds, but again, lots of people use these drives without TRIM and don't see the slowdowns.

So while TRIM is a good thing and should IMO be enabled when possible, not having it likely will not cause a problem. Even if it does and the drive slows some, it will still work.
Thanks for the info. So there should be no concern about data loss? Would a good practice be to backup, reformate and restore yearly to combat the lack of trim?
 

Weaselboy

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Thanks for the info. So there should be no concern about data loss? Would a good practice be to backup, reformate and restore yearly to combat the lack of trim?
Lack of TRIM won't impact data loss issues and a reformat is not going to resolve the issue. I would just use the drive like any other and not sweat it.
 

adamk77

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Jan 6, 2008
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Thanks for the info. So there should be no concern about data loss? Would a good practice be to backup, reformate and restore yearly to combat the lack of trim?

If you do a full reformat then it will have the opposite effect -- it'll shorten its lifespan.

A SSD is made up of blocks. A block (Block 1 below) is made up of pages (A, B, C).

Block 1
+-------------------+
| +---+ +---+ +---+ |
| | A | | B | | C | |
| +---+ +---+ +---+ |
+-------------------+

It can only write to it at the page level. Erasures can only happen at the block level. So if the SSD writes to A, B, C but then later deletes A, it would need to copy B and C to another block and then do an erase on the entire Block 1 to reclaim the freed space A. IOW, it can't just erase A without erasing the entire Block 1.

This is what's called a Write Amplification (
https://en.wikipedia.org/wiki/Write_amplification) because a single write command is amplified into multiple write operations. And this is what's happening inside a drive without TRIM.

There's not much you can do to combat this save for only reading from the SSD. So I would just use it as it is and have a sensible backup plan to mitigate data loss. Something that you can do that will improve the performance of the SSD is to keep around 20-25% of the SSD free for it to efficiently do the delete operation as described above.
 
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IngerMan

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Something that you can do that will improve the performance of the SSD is to keep around 75-80% of the SSD free for it to efficiently do the delete operation as described above.

Are you saying you should only use 20-25% of the SSD capacity or the opposite?

Also are some fo the SSD manufactures using a type of Garbage collection to combat lack of Trim?
 

adamk77

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Jan 6, 2008
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Are you saying you should only use 20-25% of the SSD capacity or the opposite?

Also are some fo the SSD manufactures using a type of Garbage collection to combat lack of Trim?

Nice catch! Yes, I got it mistakenly reversed. Fixed.

Garbage collection is already being done. It's is basically doing what I described in my earlier post but done in the background.

With or without TRIM, the flash controller should still be doing wear leveling (https://en.wikipedia.org/wiki/Wear_leveling).
 
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talk2jorge

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Lack of TRIM won't impact data loss issues and a reformat is not going to resolve the issue. I would just use the drive like any other and not sweat it.

Wow. So uninformed.

Firstly, I'd like to say I am not here for flames or trolling. I used to have an account 6 years ago but I guess it was deleted after not using it for some time.

Secondly. Wow. Just wow. Ok Is this SLC, MLC, TLC, QLC? Does this drive have cache? Is this a small drive or a large drive?

https://forums.macrumors.com/thread...on-mac-os-sierra.2119738/page-2#post-27353473

See my post here. Yes. It is supported. No Apple does not turn it on because UNMAP is not always supported by the drive enclosure. It's also up to the SSD to accept the commands as well.

The drive will expire if you have DRAM-less. It will fail if there are fewer chips (120 will fail faster than 480 or 960). If you are doing video it will fail fast. If you are always using it it will fail fast. If you are keeping it 90% full then it will fail. Garbage collection is ONLY useful if you got the cache drive. Even then I am not 100% certain that that extra cache is utilized without drivers. Definitely not on Samsung drives. Let's say you installed it IN the Mac. The over provisioning and cache is only available with driver. None of that is available on Macs. Only Windows. It'll be fast for a good month or two but slowly begin to show signs of wear.

Now for the USB 3.1 question: Here is what will happen. You'll put the drives in your enclosure. You'll use them. Next thing you know you'll be reading or writing to them and they will pause. Then the pauses will become more frequent. Then Mac will start spending extra cpu cycles on this drive because it has to keep searching for space to write and those pauses won't help. As I mentioned, I am not 100% sure the cache is effective. I am testing a 512 now. it shows up as 480 though.

NOTE: There is a reputable retailer that only sells Mac stuff. They claim to have drives specifically designed for Macs. The cache kind. They are pricey. I have not tested them but again, that is only for internal. I don't know about USB. They also sell TB PCI enclosures with PCI cards and NVME drives. It's expensive. I am not here to sell for them so I am not mentioning their name.

Ok off to see Endgame.
 
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cynics

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Jan 8, 2012
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Wow. So uninformed.

Firstly, I'd like to say I am not here for flames or trolling. I used to have an account 6 years ago but I guess it was deleted after not using it for some time.

Secondly. Wow. Just wow. Ok Is this SLC, MLC, TLC, QLC? Does this drive have cache? Is this a small drive or a large drive?

https://forums.macrumors.com/thread...on-mac-os-sierra.2119738/page-2#post-27353473

See my post here. Yes. It is supported. No Apple does not turn it on because UNMAP is not always supported by the drive enclosure. It's also up to the SSD to accept the commands as well.

The drive will expire if you have DRAM-less. It will fail if there are fewer chips (120 will fail faster than 480 or 960). If you are doing video it will fail fast. If you are always using it it will fail fast. If you are keeping it 90% full then it will fail. Garbage collection is ONLY useful if you got the cache drive. Even then I am not 100% certain that that extra cache is utilized without drivers. Definitely not on Samsung drives. Let's say you installed it IN the Mac. The over provisioning and cache is only available with driver. None of that is available on Macs. Only Windows. It'll be fast for a good month or two but slowly begin to show signs of wear.

Now for the USB 3.1 question: Here is what will happen. You'll put the drives in your enclosure. You'll use them. Next thing you know you'll be reading or writing to them and they will pause. Then the pauses will become more frequent. Then Mac will start spending extra cpu cycles on this drive because it has to keep searching for space to write and those pauses won't help. As I mentioned, I am not 100% sure the cache is effective. I am testing a 512 now. it shows up as 480 though.

NOTE: There is a reputable retailer that only sells Mac stuff. They claim to have drives specifically designed for Macs. The cache kind. They are pricey. I have not tested them but again, that is only for internal. I don't know about USB. They also sell TB PCI enclosures with PCI cards and NVME drives. It's expensive. I am not here to sell for them so I am not mentioning their name.

Ok off to see Endgame.

SSD Controllers (which is an SoC, processor, sdram (cache memory), its programming) and their associated cache work independently of the OS. The OS doesn't know what is written at a block level and the SSD doesn't know what is written at a file system level.

Only time the SSD controller get a bit more insight from the OS is when it sends the TRIM command data to make its garbage collection a more efficient.

Matter of fact the SSD controller is so independent of the OS that there is a capacitor(s) on in it so if power is lost or its removed from the computer while operating it has time to move the data off its SDRAM and onto NAND. Literally writing data while not connected to a computer albeit momentarily.

Newer controllers have a way to "refresh" the drive specifically for TRIM-less environments.

This is from a full (20gb remaining) 1tb Adata thats been in my PS4 Pro for about 2 years (upgraded it to 2tb).

Screen Shot 2019-05-11 at 9.25.14 PM.png
 

Fishrrman

macrumors Core
Feb 20, 2009
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All I can do is report on my own experiences, over the course of several years.

I've never had a "TRIM" problem with any SSD I've used, for booting or otherwise.
That includes drives mounted via USB3, USB2, firewire.
Boot drives, data drives, no difference.

TRIM is a molehill that some folks transformed into a mountain.
It might affect you, but the chances are few. For most folks, I reckon it will never come into distant view.
 
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mikehalloran

macrumors 68000
Oct 14, 2018
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The Sillie Con Valley
Wow. So uninformed.

Firstly, I'd like to say I am not here for flames or trolling. I used to have an account 6 years ago but I guess it was deleted after not using it for some time.

Secondly. Wow. Just wow. Ok Is this SLC, MLC, TLC, QLC? Does this drive have cache? Is this a small drive or a large drive?

https://forums.macrumors.com/thread...on-mac-os-sierra.2119738/page-2#post-27353473

See my post here. Yes. It is supported. No Apple does not turn it on because UNMAP is not always supported by the drive enclosure. It's also up to the SSD to accept the commands as well.

The drive will expire if you have DRAM-less. It will fail if there are fewer chips (120 will fail faster than 480 or 960). If you are doing video it will fail fast. If you are always using it it will fail fast. If you are keeping it 90% full then it will fail. Garbage collection is ONLY useful if you got the cache drive. Even then I am not 100% certain that that extra cache is utilized without drivers. Definitely not on Samsung drives. Let's say you installed it IN the Mac. The over provisioning and cache is only available with driver. None of that is available on Macs. Only Windows. It'll be fast for a good month or two but slowly begin to show signs of wear.

Now for the USB 3.1 question: Here is what will happen. You'll put the drives in your enclosure. You'll use them. Next thing you know you'll be reading or writing to them and they will pause. Then the pauses will become more frequent. Then Mac will start spending extra cpu cycles on this drive because it has to keep searching for space to write and those pauses won't help. As I mentioned, I am not 100% sure the cache is effective. I am testing a 512 now. it shows up as 480 though.

NOTE: There is a reputable retailer that only sells Mac stuff. They claim to have drives specifically designed for Macs. The cache kind. They are pricey. I have not tested them but again, that is only for internal. I don't know about USB. They also sell TB PCI enclosures with PCI cards and NVME drives. It's expensive. I am not here to sell for them so I am not mentioning their name.

Ok off to see Endgame.
There is so much that you don’t know about this. Yikes! This whole post should be ignored.
 
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mikehalloran

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Oct 14, 2018
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Only time the SSD controller get a bit more insight from the OS is when it sends the TRIM command data to make its garbage collection a more efficient.
For the most part, true.

Matter of fact the SSD controller is so independent of the OS that there is a capacitor(s) on in it so if power is lost or its removed from the computer while operating it has time to move the data off its SDRAM and onto NAND. Literally writing data while not connected to a computer albeit momentarily.
Although some enterprise SSDs such as the Samsung 845 EVO have this capacitor bank, I’m unaware of a single consumer drive having this feature. Not one.

About 10 days ago, I lost all data on 4T of external SSDs during a power outage. It was a freak occurrence that involved a power outage while I was powering up a new Thunderbolt dock for the first time. My 845 EVO was not one of the drives. No big deal, a reformat and Time Machine restore brought both back to life. TRIM or the lack thereof had nothing to do with and could not have prevented it.

I've never had a "TRIM" problem with any SSD I've used, for booting or otherwise.
That includes drives mounted via USB3, USB2, firewire.
Boot drives, data drives, no difference.
Well, since on a Mac, TRIM cannot be enabled on any of those drives, it cannot be an issue. Trim over USB works on Linux but not on the Mac.

TRIM is a molehill that some folks transformed into a mountain.
It might affect you, but the chances are few. For most folks, I reckon it will never come into distant view.
You’re right since pretty much no one knows what it is or how it works.

TRIM is built into the OS with Windows, most UNIX including Linux and Mac OS since 10.7.

The Mac OS is the only one that blocks TRIM on certain SSDs that the OS sees as 3rd party. NVMe SSDs over PCIe are an exception as they are when you boot from one over Thunderbolt. Otherwise, you can enable TRIM by running sudo trimforce enable in Terminal from OS 10.10.4 on. If running an external SATA III SSD over Thunderbolt, TRIM is not enabled on them until that command is run.

What does it do? It allows Garbage Collection to run more efficiently and prolongs the life of SSDs. There are ways to observe and measure the differences in efficiency between having it enabled and not but it’s best run on a Mac booting from an internal SATA SSD and a few days to properly load the drive, then a few more to observe how long it takes for garbage collection to work. Without TRIM, a 1TB drive takes 36–48 hours. With TRIM enabled, less than 24. Best to format APFS or you’ll be unable to observe the results. You’ll need TechTool Pro or a similar tool.
 
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