Is enabling TRIM on Samsung 840 Pro SSDs safe?

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Level 1

29 points

Is enabling TRIM on Samsung 840 Pro SSDs safe?

I'm still at Yosemite due to compatibility issues with some software we're using at work. I saw that from OS X 10.10.4 you can enable TRIM from terminal, which would help a lot on my MBP 2011 with a Samsung 840 Pro 256GB. When I bought it, it was peaking at about 500MB/s both read/write - excellent! But newer benchmarks shows a sad score:

This is obviously a result of poor built-in garbage collection and the lack of TRIM support on OS X. While it is easy to enable TRIM, I'm not so sure that it is safe to enable it. There are a lot of articles from 2014 and 2015 mentioning bugs in Samsung's firmware regarding queued TRIM, and bugs in the Linux kernel regarding sequential TRIM which created a different issue. Most people would have problems due to the firmware issue on the drive.

So - where are we now? Is this still an issue? I can't find more recent post on what the potential risks are. I'm doing a lot of video importing/exporting at the time (hence the wish for a faster drive) and I can't risk any corruptions. We're talking maybe 50-60 hours of material, so any corruption in the exports would probably take a long time to notice (before anyone watches all the material).

A quote from the MacRumors post: "So if you've got a modern Samsung drive, it's important that your OS uses regular sequential TRIM. Linux is the only OS that uses queued. All versions of OS X (even El Capitan) and Windows (latest) still use sequential TRIM, and will continue to do so for the foreseeable future."

So is this true? I can without any problems activate trim on my Samsung SSD, no risks that I'm suddenly stuck with random corruptions on my files in a few days/weeks?

Posted on May 23, 2016 1:26 AM

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Answer 1

KeyDemon Author

Level 1

29 points

May 23, 2016 2:17 AM in response to KeyDemon

As far as I can see from this article from 'about tech' there shouldn't be any problems on Mac, only those Linux distributions which uses queued TRIM, which the Samsung 840/850 drives incorrectly informs that it supports. Sequential TRIM and Mac/Windows shouldn't see any problems.

"Samsung TRIM issues seem to only become apparent when used with queued TRIM commands. OS X only makes use of sequential TRIM commands at this time, so enabling TRIM with the Samsung line of SSDs should be OK, as reported by MacNN."

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Answer 2

May 23, 2016 12:06 PM in response to KeyDemon

Enabling TRIM is a good idea though it would be wise to ensure your firmware is up-to-date first. Note that TRIM involves reporting the freeing up of drive space due to file deletion to the SSD controller when the deletion takes place; since it's not retroactive, it can't look back in time to report previous deletions to aid in Garbage Collection.

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Answer 3

May 23, 2016 5:54 PM in response to KeyDemon

KeyDemon wrote:

So is this true? I can without any problems activate trim on my Samsung SSD, no risks that I'm suddenly stuck with random corruptions on my files in a few days/weeks?

Your best bet is to talk to Samsung support for their recommendation and experience.

You have to do your due diligence and comoe to your own conclusion—since you assume the risk.

The advantage of the TRIM command is that it enables the SSD’s GC to skip the invalid data rather than moving it, thus saving time not rewriting the invalid data. This results in a reduction of the number of erase cycles on the flash memory and enables higher performance during writes. The SSD doesn’t need to immediately delete or garbage collect these locations it just marks them as no longer valid.

ref: http://www.thessdreview.com/daily-news/latest-buzz/garbage-collection-and-trim-i n-ssds-explained-an-ssd-primer/

trimforce enable

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Answer 4

BobHarris

Level 9

55,055 points

May 23, 2016 6:16 PM in response to KeyDemon

I have been using TRIM for about a year on my Samsung 1TB 840 EVO in my Macbook Pro, running both Mavericks and El Capitan.

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Answer 5

KeyDemon Author

Level 1

29 points

May 24, 2016 12:28 AM in response to BobHarris

After reading through a lot of articles, it seems like it's only "queued TRIM" that can corrupt the data on Samsung SSD's. It seems like Linux is still the only ones that use queued, while OS X is using sequential TRIM. If this should ever change, the bug in Samsung's firmware could give data loss.

But for now, it seems absolutely safe to enable TRIM, so I did.

After a reboot, my computer got a "Forbidden" symbol on screen, nothing else. Rebooted while holding Option(Alt) and selected Recovery (Which was called 10.10.3, even though I'm at 10.10.5).

After reinstalling OS X (not wiping the drive!) I was back on the desktop, and still on 10.10.5. I did re-download that update and run it to be absolutely sure all system files were the most recent version.

After cleaning up some files on my hard drive, I rebooted and held "CMD + S" to start in Single-User mode. From here I wrote "fsck -fy" and let it run, then did it another time. Filesystems were OK both times, but this also forces TRIM to do its thing.

The results speaks for it self:

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Answer 6

May 24, 2016 7:33 AM in response to KeyDemon

KeyDemon wrote:

The results speaks for it self:

Good computing KeyDemon !

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