SSD in USB Enclosure - Trim Support?

[That-Guy]

I have just upgraded the SSD in my Mac Mini to a Samsung 840 Evo which is working great with Trim enabled using Trim Enabler.

I have put my old OCZ SSD in a USB 3.0 Enclosure and it works fine.

My questions are:

- Do USB SSDs still use Trim?

- If so how do I check its working? As I can't see it in the system report.

- If USB SSDs don't use Trim does this affect the drive?

Thanks in Advance

 

[Intell]

I believe TRIM is only for drives connected via SATA and eSATA.

 

[That-Guy]

I believe TRIM is only for drives connected via SATA and eSATA.

Thanks

Do you know if not having Trim running on the external drive will cause any issues? or do USB SSDs work in a different way?

Thanks in Advance!

 

[wannabepcuser]

I have an ssd connected to my iMac through a thunderbolt enclosure. The trim enabler app I have says that trim is enabled.

 

[Intell]

I have an ssd connected to my iMac through a thunderbolt enclosure. The trim enabler app I have says that trim is enabled.

That's because the Thunderbolt drive has an internal SATA chipset that supports it.

 

[That-Guy]

Ah just found this:

SSDs have great performance, but this performance does “drop off” after a while due to the consumption of flash blocks and the lack of spare blocks to do wear levelling with. Modern OSes have used a system called TRIM which allows the OS to signal to the drive when certain sector ranges no longer contain useful data, letting the SSD erase and use those blocks in the wear levelling process, or consolidate many larger pages with little useful data into one block. Unfortunately, being connected via USB is likely to prevent TRIM from functioning.

From here: http://goughlui.com/?p=2304

No matter, will just use it until it fails. Im sure this OCZ Vertex Plus SSD I am using isn't worth anything and the enclosure only cost me £8

 

[Weaselboy]

Thanks

Do you know if not having Trim running on the external drive will cause any issues? or do USB SSDs work in a different way?

Thanks in Advance!

No TRIM over USB like you discovered. It won't kill the SSD or anything. All that will happen is it will accrue write cycles slightly faster and over time the write speeds may slow a bit from no TRIM. This is not permanent damage though. You could always put the drive in a TB or eSATA connection and run "fsck -ffy" in Terminal against the drive and that would TRIM all free space and restore write speeds to like new.

 

[That-Guy]

No TRIM over USB like you discovered. It won't kill the SSD or anything. All that will happen is it will accrue write cycles slightly faster and over time the write speeds may slow a bit from no TRIM. This is not permanent damage though. You could always put the drive in a TB or eSATA connection and run "fsck -ffy" in Terminal against the drive and that would TRIM all free space and restore write speeds to like new.

So when it slows down can I just re-format the drive to speed it up? or will I need to use the Trim Command above along with another Enclosure?

I won't be using it as a backup drive or anything it will only be used occasionally for transporting non-important files.

 

[Weaselboy]

So when it slows down can I just re-format the drive to speed it up? or will I need to use the Trim Command above along with another Enclosure?

I won't be using it as a backup drive or anything it will only be used occasionally for transporting non-important files.

No you don't need to reformat, you would need to execute that fsck command from a TRIM compatible connection like eSATA or TB. If you are not using the drive that much like you describe, it will very likely never even be an issue.

 

[Fishrrman]

OP wrote above:
[[ So when it slows down can I just re-format the drive to speed it up? or will I need to use the Trim Command above along with another Enclosure?
I won't be using it as a backup drive or anything it will only be used occasionally for transporting non-important files. ]]

My advice, will be different from others:

If the drive will only "be used occasionally for transporting non-important files", then I don't think the lack of TRIM will affect the drive's performance in any way that you can perceive.

Just put the drive into the USB3 enclosure, and use and enjoy it.

My personal experience:
I bought a late-2012 Mini in January 2013. I used it for about 9 months with an "external booter" -- an Intel 530 series SSD mounted in a plugable.com USB3 "lay-flat" dock. Never had TRIM enabled, very little downgrade in perceptible speeds (none, actually). I've since moved that drive into a 2010 MacBook Pro, and I now use a Crucial m500 SSD as my external booter. Again, runs fine without TRIM, speed is where I would expect it to be.

I sense the "issue of TRIM" can get blown up out-of-proportion. It probably doesn't impact things as heavily as some would argue. In the case of an "external booter" via USB3, if one ever did believe the drive was slowing noticeably, it could probably be "re-conditioned" with the right tools.

Aside: I'm surprised that no software developer has yet to come out with an app that is purposely-designed to "restore" an SSD to "factory-fresh" condition. I know that with the right toolset, this can be done manually, but what's needed is a "hit the button and go" app that accomplishes this on the Mac. Could be a good seller.