Yosemite, Trim Enabler, NV RAM reset & Safe Boot etc.

[mikehalloran]

Since James is making this a sticky, I will update it a bit:

TRIM

TRIM is a drive management system that is part of OS X. It manages unused space, deleted files and prolongs the life of SSDs. The problem is that Apple blocks TRIM from working unless the OS detects an Apple original equipment (OE) SSD.

Trim Enabler

Although there are command lines that you can run in Terminal to unblock TRIM, there is an app that can do this for you. Trim Enabler.app is shareware – its core function (unblock TRIM) works if you don't pay the $10 but the shareware fee allows all of its features to work. One of those features is a pop-up every time you run an OS update that tells you that the app has been disabled. There's other functionality, too.
https://www.cindori.org/software/

Issues and what to do if you cause them

Kext signing is a new security "feature" in Yosemite. Because Trim Enabler turns it off (unblocking TRIM is not approved by Apple, after all), there are issues if you don't remember to disable it before performing certain functions.

It is known that in Yosemite, if you reset the NV RAM (PRAM) with Trim Enabler on, your Mac won't boot from that drive until you fix it. This is true for both spinners and SSDs – I can verify this. I now know that a Safe Boot will cause the same result (guess how I found out?).

Anyway, if that happens to you there are three ways to fix this:

1) Follow the instructions at Cindori's web site Terminal Commands:
http://www.cindori.org/trim-enabler-and-yosemite/
If you are comfortable with Terminal commands, this is the fastest way.

2) If you have another partition or drive with OS X, Option-Boot into it. Download the latest Combo Update from Apple. Install it onto the affected drive. Select it as your boot drive and restart. It is the easiest of the three methods. However, if you have installed an update after the last Combo Update, your Mac may not let you install this. If so, try downloading the latest build of OS X from the App Store (check Purchases or Featured) – it needs to be the latest build if Combo Update doesn't work. If that won't install or you do not have another bootable drive or partition, you must…

3) Option-Boot into the Repair partition, select Reinstall OS X. This takes a lot longer than either of the other methods (an hour on my system). It's the only way if you don't want to mess with Terminal and don't have another drive or partition to boot in. This does not affect your data, it only reinstalls the OS and updates your Repair partition.

When I accidentally caused this on my mechanical HD, it took awhile to figure out that Safe Boot with Trim Enabler on was the culprit. Once I figured it out, I decided to break and fix both drives a few times just to see what worked.

In case it happens to you.

[Phil O]

Great info Mike. Can we make this a sticky?

[MIDI Life Crisis]

Is Trim necessary on a newer model Mac/SSD? Seems like a bit of a liability. Isn't there some app to accomplish the same thing users can run at will?

[mikehalloran]

Is Trim necessary on a newer model Mac/SSD? Seems like a bit of a liability. Isn't there some app to accomplish the same thing users can run at will?

In the case of your nMP, this is not an issue. The internal drive is Trimmed automatically by the OS. Safe Boot, NV RAM reset, go ahead – it's not affected. This is true for any Mac that boots from a factory installed Apple SSD.

Trim Enabler is for non-Apple OE SSDs. You can use Trim Enabler as an app with Apple Disk Utility. Here's how.

Install Trim Enabler. Turn it on and re-boot. The drive can be your boot disk. (If running from an external drive, it must be connected via SATA, eSATA or PCIe via Thunderbolt. Straight TB and/or USB will not work for this. If you can't read S.M.A.R.T. Status, Trim from an external won't work either).

On occasion, with Trim Enabler on, run Repair Disk from Apple Disk Utility. Run it on your SSD - the entire drive, not the named partition. You will get a report like the following (bold is mine):

Verifying and repairing partition map for “Samsung SSD 845DC EVO 960GB Media”
Checking prerequisites
Checking the partition list
Adjusting partition map to fit whole disk as required
Checking for an EFI system partition
Checking the EFI system partition’s size
Checking the EFI system partition’s file system
Checking all HFS data partition loader spaces
Checking booter partitions
Checking booter partition disk1s3
Repairing file system.
Checking Journaled HFS Plus volume.
Checking extents overflow file.
Checking catalog file.
Checking multi-linked files.Checking catalog hierarchy.
Checking extended attributes file.
Checking volume bitmap.
Checking volume information.
Trimming unused blocks.
The volume Recovery HD appears to be OK.
File system check exit code is 0.
Updating boot support partitions for the volume as required.
Reviewing boot support loaders
Checking Core Storage Physical Volume partitions
Updating Windows boot.ini files as required
The partition map appears to be OK


When done, open Trim Enabler, set it to Off and reboot.

[MIDI Life Crisis]

Cool. Thanks! Now how do I loose that 20 pounds I found?

[mikehalloran]

I have recently tested Disk Warrior and TechTool Pro 8.0.1 on drives with Trim Enabler.app on.

They work and the system reboots properly.

For some reason, there are performance issues in both tools with Yosemite 10.10.3 but I can't link them to Trim Enabler (turning it off makes no difference). Disk Warrior is at version 5 and TTP well, just has issues.

The point is that using these on or from a drive with Trim Enabler on will not cause your drive to fail to boot. Same goes for Apple Disk Utility.

[James Steele]

Great info Mike. Can we make this a sticky?

Yes... yes, we can!

[Phil O]

Thank you, James.

[Michael Canavan]

In No way am I implying that this isn't a valid conversation and Mikes information is great! but I think it anyone interested in this subject should read this chat I had with a representative from RAM City, and the links he posted. I bought the Samsung XP941 from this Australian outfit, they seem like a good company, they share a lot of information which I really appreciate.

Hello Michael. What brings you to RamCity?
4:45 pm
Michael
Hi Rod, a question actually. I ordered one of the Samsung XP941 SSDs and installed it a while ago in a Mac Pro. The service guyy I worked with said that the lack of TRIM support wasn't a deal at all if you
weren't writing 10GB of data a day
4:46 pm
Rod Bland
yes, that's my view as well. TRIM is useful no doubt, but unlikely to make much of a difference unless you are writing a lot of data to the drives on a daily basis.
4:48 pm
Michael
For the record what is a 'lot of data'? I have a lot of friends in the music industry and they get nuts about using TRIM enabler,
4:48 pm
Rod Bland
I don't have a hard and fast rule, and especially with the XP941, the speed benefit it brings far outweigh the benefit of TRIM on a slower SATA based SSD.
4:49 pm
Michael
Right, I just see a lot of people worrying about this, and I can't find any information on a good SSD that was compromised because TRIM wasn't supported.
4:50 pm
Rod Bland
yes, but i think it's still useful to compare Apples to Apples, so to speak. If say, you are writing 100GB of data per day to the drive, then one could expect better performance and endurance from say, an Angelbird brand SSD in a mac (which has native trim support on Yosemite), versus a Crucial or Samsung.
4:52 pm
for some, the TRIM feature is more important to them than higher performance, which doesn't always make sense, especially if high performance results in higher productivity
4:53 pm
Michael
100GB would be basically 10 albums a day worth of recording. IMO it seems like only servers would break 100GB on a daily?
4:53 pm
Rod Bland
yes, I agree
4:54 pm
I think most conversations about TRIM don't always factor in performance. Since we are talking about the XP941, my view is that TRIM is non-issue given that it runs at 2-3 times the rate of a standard SATA SSD. And in the end, if TRIM really matters to you, then go ahead and disable KEXT and enable it with trim enabler.
4:56 pm
Michael
Right, I guess my feeling is TRIM actually doesn't seem to matter, even on a run of the mill Crucial, unless you're running a server. So far three months later, no slow down in Performance on the XP941
4:57 pm
Rod Bland
Yes, and that makes sense, given that TRIM really just speeds up the garbage collection process. After a period of time with low activity, the GC process will catch up of it's own accord, even without TRIM.
4:59 pm
Michael
Yeah, I'm going to continue to not use TRIM and continue to monitor the drive speed, my guess is garbage collection is going to 100% work, with no slow down, but I'm happy to be proven wrong if a year from now I see a slower drive without filling it to capacity etc.
5:00 pm
Also, do you mind if I publish this to a forum? I will replace your name and not quote your business if that's an issue.

5:01 pm
Rod Bland
No problems, freedom of speech and all that. I always respond to forum comments usually if I think additional context is needed. I also wrote a blog post about TRIM a while ago which may be of interest: https://www.ramcity.com.au/blog/trim-an ... ite/139474
5:02 pm
there is a previous blog post I linked to in that article which also describes TRIM in more detail, with references for further reading.
https://www.ramcity.com.au/blog/all-abo ... sds/139473
5:02 pm
Michael
Very cool, it's a professional audio forum, so all respectable people etc.
Rod Bland
sounds like a perfect match for RamCity!
5:03 pm
Michael
Thanks for your time! have a good evening/day
5:04 pm
Rod Bland
cheers Michael - thanks for the chat.

[mikehalloran]

Mr. Bland has a product to sell. He states that TRIM isn't necessary then points to a premium priced product with midrange performance that fools the OS into thinking its an Apple OE drive so that TRIM works. The other links he points to disagree with him on the need for TRIM if you follow them.

OK, fine. We have other, older threads on whether TRIM is necessary or not. If you want to start another, knock yourself out. This one isn't about that. It's about Trim Enabler.app and Yosemite and what does and doesn't work in that context. Let's keep it there.

[Michael Canavan]

Mr. Bland has a product to sell. He states that TRIM isn't necessary then points to a premium priced product with midrange performance that fools the OS into thinking its an Apple OE drive so that TRIM works. The other links he points to disagree with him on the need for TRIM if you follow them.

OK, fine. We have other, older threads on whether TRIM is necessary or not. If you want to start another, knock yourself out. This one isn't about that. It's about Trim Enabler.app and Yosemite and what does and doesn't work in that context. Let's keep it there.

I hear you, the other threads are also his writing. He's selling Angelbird in the links for sure, but the information given is given.The point I'm getting at is even through his sales pitch etc. is that garbage collection these days works fine at under roughly 10GB writes per day, and his quote on when it's a possible problem is 100GB of writes. That he tries to sell the Angelbird SSDs is irrelevant to that.

Mostly my point remains the same, that this is a great fix for a possible problem. The truth is if you're running a 400-550mbs SSD on the SATA bus of a Mac Pro, you're already bottlenecked to 300mbs and there's no way you would even notice any loss in performance from lack of TRIM. Under circumstances where you're running on the PCIe bus it's possible, but in my case so far there isn't a single element of degradation in performance from three months ago with the SSD running on the PCIe bus.

I'm sorry that you see a differing opinion to yours on the issue as irrelevant in this thread. I don't agree with that, there isn't a current consensus on the worth of compromising security on your OS VS the benefits of TRIM. So far I see no degradation in performance with the SSD installed and I will honestly tell you if I do, but when multiple sites suggest that you have to write more than 10GB worth of data for garbage collection to not catch up and degrade performance I tend to think it's not much of an issue.

I think the suggestion to run Trim Enabler every couple of months, then turn it off as to not put a hole in security is probably the best compromise between our talking points here.

[mikehalloran]

OK, I must be the canary in the coal mine. I downloaded Soundflower 1.6.6b, installed, saw the "out of date certificate" and thought, "uh oh...".

Sure enough, on reboot, I got the big circle with the slash. So, I option-booted into my other drive, reinstalled the OS – since I keep a fresh copy on that drive, it takes only 19 minutes. And was up and running.

Next I crossed my fingers and tried reactivating Trim Enabler. After two reboots, everything was great.

Soundflower 1.6.6b, BTW, works great in Yosemite. Here is the official download site:
https://rogueamoeba.com/freebies/soundflower/

Turn Trim Enabler.app Off and reboot before installing Soundflower.

I wonder … what's next?

[mikehalloran]

I think the suggestion to run Trim Enabler every couple of months, then turn it off as to not put a hole in security is probably the best compromise between our talking points here.

I already gave instructions for running it from another drive if one is that concerned – you do not have to enable it on your boot drive at all. The only caveat is that it must be connected via SATA or eSATA or be a partition.

I haven't tried running it from an eDrive in TechTool Pro yet. I have a really busy weekend – perhaps I'll get to it tomorrow evening. Stay tuned.

[daniel.sneed]

For security reasons, I've been reluctant to set Trim enabler on in Yosemite. So I decided to go with Trim enabler off.

My actual workaround:
Every 3 monthes, I run iDefrag on all my drives.
Then boot from an old 10.9 drive, run diskutility on all drives.
10.9 Diskutility does include a "trim unused blocks" function.
Boot again from my main drive and voila.

[mikehalloran]

You should never run iDefrag on an SSD. It is not necessary and will shorten the life over time. Other tools like TechTool Pro will not defrag an SSD.

If Disk Utility is trimming unused blocks in Yosemite, you must have an Apple SSD or that Austrian drive that fools the OS. If so, none of this thread applies. The OS runs Trim automatically.