TRIM Support no longer 'easy' in Yosemite

[mrf5]

It sounds like you were booted to the OS and enabled trim, then booted to the recovery partition and tried to run the disk repair (believing that Trim would be enabled there too).

Activating Trim from the normal OS, does not enable Trim for the restore boot partition. That's why I wanted to know how you enabled Trim for a restore boot partition. It can be done I assume, but I don't personally know how.

I booted into full install of Mavericks (on a different physical disk), enabled Trim, then ran the repair.

Thanks. That makes more sense.

Regarding trimming a disk from the recovery partition:

Hmmm ... I believe you are correct here and I was mistaken above (it has been a long time since I booted a recovery partition). I have several bootable system disks in my Mac and it is easier just to reboot to one of them with trim enabled and then repair disk the other drive to trim unused blocks. Thanks for correcting this!

I will correct my post above ... sorry for misleading anyone here.

Imo, there was no misleading here. I used to have several bootable system disks in the past, but now i’m down to the recovery partition. Repair Disk isn’t a big deal for me. Fsck will do for now. Thanks again for your help

btw, if u install Yosemite, does it auto install recovery partition? (assuming u updated to Yosemite)

 

[Weaselboy]

btw, if u install Yosemite, does it auto install recovery partition? (assuming u updated to Yosemite)

Yes it will.

 

[macthefork]

Unless I'm mistaken, if you boot into a Mavericks partition to run TRIM, the TRIM routine will clean up the disk related to trashed and OS discarded items (such as temporary files) only for Mavericks. Since TRIM is an OS controlled routine that is run on the SSD, what may be discarded or trashed in a Yosemite partition may not be seen if the TRIM routine is run from Mavericks.

I'm not sure if Mavericks could see and identify trashed and discarded items from another OS like this and determine that they are indeed identified for the TRIM routine.

I could be wrong, but that was my understanding--that it is very OS dependent.

 

[crjackson2134]

Unless I'm mistaken, if you boot into a Mavericks partition to run TRIM, the TRIM routine will clean up the disk related to trashed and OS discarded items (such as temporary files) only for Mavericks. Since TRIM is an OS controlled routine that is run on the SSD, what may be discarded or trashed in a Yosemite partition may not be seen if the TRIM routine is run from Mavericks.

I'm not sure if Mavericks could see and identify trashed and discarded items from another OS like this and determine that they are indeed identified for the TRIM routine.

I could be wrong, but that was my understanding--that it is very OS dependent.

Yes, you are very mistaken. Try it...

 

[VirtualRain]

Unless I'm mistaken, if you boot into a Mavericks partition to run TRIM, the TRIM routine will clean up the disk related to trashed and OS discarded items (such as temporary files) only for Mavericks. Since TRIM is an OS controlled routine that is run on the SSD, what may be discarded or trashed in a Yosemite partition may not be seen if the TRIM routine is run from Mavericks.

I'm not sure if Mavericks could see and identify trashed and discarded items from another OS like this and determine that they are indeed identified for the TRIM routine.

I could be wrong, but that was my understanding--that it is very OS dependent.

Yes, you are very mistaken. Try it...

TRIM is simply the passing of information about deleted files from the OS level file system to the physical media. The OS on any given partition can only TRIM blocks that belong to it.

http://en.wikipedia.org/wiki/Trim_(computing)

If you have multiple partitions governed by different operating systems, they should all be running TRIM for optimum performance. The recovery partition is, of course, a special case and can be ignored as it's not used in everyday computing so performance degradation is not a concern.

 

[macthefork]

Yes, you are very mistaken. Try it...

How are you sure that running TRIM from Mavericks will actually TRIM a Yosemite partition? I'm sure TRIM runs, since I run it from a Mavericks partition. But is the routine actually doing it's job on the Yosemite SSD partition in addition to the Mavericks SSD?

Saying I'm mistaken is fine, and I may well be. However, I still would like to know how a TRIM routine run from an earlier OS can determine everything that is discarded or trashed within a newer OS in order to properly re-allocate the blocks.

In other words, how is this verified?

 

[crjackson2134]

if you mount the drive from Mavericks, use the Disk Utility to Trim all unused blocks, and keep trim active on the booted OS, Trim will do its thing. If you erase or mov files around on the SSD while booted to your Trim Enabled OS, it will manage the changes properly.

If you think I'm wrong, then so be it. If it didn't work this way, then Trim s totally useless for storage drives.

 

[VirtualRain]

When you mount the drive in question, it's seen as any other SSD storage volume with Trim enabled. I'm sorry my answer isn't more detailed. I'm VERY ill at the moment, ant I just don't feel like a lengthy reply. The information is out there, you just need to search around and read it. Hopefully someone else will chime in and explain it to you. I probably shouldn't have replied at all.

Yes, this is true and I see what you're saying. If you have a drive with two OS X partitions (such as 10.10 and 10.9) and you boot to 10.10, the 10.9 partition will still mount as a regular storage volume (even though you may not be using it). If you delete any files off the 10.10 or 10.9 volumes, TRIM will act as expected. Conversely, if you boot the 10.9 partition, the 10.10 partition will mount as a storage volume and still be subject to TRIM if any files are deleted from that volume.

What I was thinking (and perhaps Macthefork was thinking this as well), was that if you have an OS X partition and a Windows NTFS partition, obviously each of those partitions operate completely independently (neither will mount the other) so they can't possibly TRIM each other's volumes, but then you can't delete files off the other volume anyway.

 

[crjackson2134]

TRIM is simply the passing of information about deleted files from the OS level file system to the physical media. The OS on any given partition can only TRIM blocks that belong to it.

http://en.wikipedia.org/wiki/Trim_(computing)

If you have multiple partitions governed by different operating systems, they should all be running TRIM for optimum performance. The recovery partition is, of course, a special case and can be ignored as it's not used in everyday computing so performance degradation is not a concern.

If the file system is mounted on the other SSD, the blocks are still marked as deleted. The deleted areas can't be used however until the pages are empty. Trim can read the deletion markers on the other SSD just fine, this is how the whole "Trimming Unused Blocks" function works. If you are mounting that file system and continue to make changes to that particular SSD (provided it has trim support) with the Trim Enabled OS, Trim will continue to function (just like it does when you add a Trim enabled SSD storage drive).

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What I was thinking (and perhaps Macthefork was thinking this as well), was that if you have an OS X partition and a Windows NTFS partition, obviously each of those partitions operate completely independently (neither will mount the other) so they can't possibly TRIM each other's volumes, but then you can't delete files off the other volume anyway.

Well I had no idea we were referring to unsupported file systems. To my knowledge, you can't manipulate files on an unsupported file system, thereby making the question irrelevant. I thought we were talking about mounting the file system of a Yosemite install while booted into a Mavericks install. Anyway I stand by my statement. I've done it often...

 

[VirtualRain]

If the file system is mounted on the other SSD, the blocks are still marked as deleted. The deleted areas can't be used however until the pages are empty. Trim can read the deletion markers on the other SSD just fine, this is how the whole "Trimming Unused Blocks" function works. If you are mounting that file system and continue to make changes to that particular SSD (provided it has trim support) with the Trim Enabled OS, Trim will continue to function (just like it does when you add a Trim enabled SSD storage drive).

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Well I had no idea we were referring to unsupported file systems. To my knowledge, you can't manipulate files on an unsupported file system, thereby making the question irrelevant. I thought we were talking about mounting the file system of a Yosemite install while booted into a Mavericks install. Anyway I stand by my statement. I've done it often...

No, you're absolutely correct, it just wasn't intuitive at first as I've never run multiple partitions on the same drive in OS X but it makes total sense now that I think about it.

 

[crjackson2134]

In other words, how is this verified?

Boot to Mavericks with Trim enabled.

Mount the Yosemite file system

Open disk utility and select the Yosemite partition

Click the repair disk function

Watch the progress on the log window

Notice at the end of the log, it reports "Trimming unused blocks"

Realize that trim is working, otherwise it couldn't "Trim Unusd Blocks"

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No, you're absolutely correct, it just wasn't intuitive at first as I've never run multiple partitions on the same drive in OS X but it makes total sense now that I think about it.

I didn't really feel like explaining right now, so I should have never replied in the first place. Sorry for the brevity of my first answer. I thought the OP just wanted his question answered, so I did. Lesson learned, I'll try not to participate when on treatment days. I just don't have the energy.

 

[VirtualRain]

I didn't really feel like explaining right now, so I should have never replied in the first place. Sorry for the brevity of my first answer. I thought the OP just wanted his question answered, so I did. Lesson learned, I'll try not to participate when on treatment days. I just don't have the energy.

No worries... your response was perfectly fine IMHO.

MactheFork, I think one way to look at it is that when you boot 10.9, and mount the 10.10 volume... 10.9 owns it as long as it's mounted (the fact that it's also bootable is irrelevant) and 10.9 will TRIM the 10.10 volume if you delete anything significant from it or Repair it.

 

[crjackson2134]

MactheFork, I think one way to look at it is that when you boot 10.9, and mount the 10.10 volume... 10.9 owns it as long as it's mounted (the fact that it's also bootable is irrelevant) and 10.9 will TRIM the 10.10 volume if you delete anything significant from it or Repair it.

Exactly correct, and well put.

 

[macthefork]

Makes sense... Thanks to both of you (rain and jackson) for your clear explanations.

 

[h9826790]

In the Mavericks point of view, that Yosemite partition is just a "Mac OS Extended (Journaled)" partition, of course it can TRIM that partition. Otherwise, it means Mavericks can only TRIM it's own boot partition, which doesn't make any sense at all.

That partition bootable or not? Doesn't matter. And Mavericks should know nothing about Yosemite anyway.

 

[mrf5]

^ Great discussion!

(assuming there is away to enable trim on 10.10 recovery-partition)
Q. Is 10.10 recovery-partition also requires Kext-signing? or is it relaxed?

 

[Cindori]

^ Great discussion!

(assuming there is away to enable trim on 10.10 recovery-partition)
Q. Is 10.10 recovery-partition also requires Kext-signing? or is it relaxed?

Since you will not be modifying any files on the recovery partition, it makes no sense to need disable kext-signing to boot it. The recovery partition is a whole separate set of system files.

 

[thefredelement]

Since you will not be modifying any files on the recovery partition, it makes no sense to need disable kext-signing to boot it. The recovery partition is a whole separate set of system files.

Hi Cindori, do you think it'd be possible to hack our SSDs to mimic Apple branded SSDs?

Or do you think it would be possible to custom add other SSDs to their OK list to enable trim? - or is this also part of their private controller stack? I'm really thinking it just has to be a list somewhere...

 

[flowrider]

Hi Cindori, do you think it'd be possible to hack our SSDs to mimic Apple branded SSDs?

One vendor is doing just that:

http://www.angelbird.com/en/prod/ssd-wrk-for-mac-pro-937/

Lou

 

[h9826790]

So, if I have an Apple SSD in my Mac, TRIM will be automatically activated for all other SSD, right?

 

[Weaselboy]

So, if I have an Apple SSD in my Mac, TRIM will be automatically activated for all other SSD, right?

No it won't. If you have other non-Apple OEM SSDs in there TRIM will not be activated on those drives without the hack.

 

[thefredelement]

One vendor is doing just that:

http://www.angelbird.com/en/prod/ssd-wrk-for-mac-pro-937/

Lou

That was my inspiration for asking the question.

I wonder how Apple has the list of OK SSDs, and how it stores them. If it's hidden in some plain text way somewhere, I'd be really hopeful that Cindori can work out a way to get a new version of Trim Enabler to add an SSD to that list. I've been looking around in terminal but honestly have no idea where to look. - If it's stored as a kernel extension in a compiled piece of code, that'd be a bummer.

If not, maybe he can figure out a way to flash the ID of the card, or at least it's representation to the system, without having to get his hands dirty with disabling kext signing.

 

[mikeboss]

That was my inspiration for asking the question.

I wonder how Apple has the list of OK SSDs, and how it stores them. If it's hidden in some plain text way somewhere, I'd be really hopeful that Cindori can work out a way to get a new version of Trim Enabler to add an SSD to that list. I've been looking around in terminal but honestly have no idea where to look. - If it's stored as a kernel extension in a compiled piece of code, that'd be a bummer.

If not, maybe he can figure out a way to flash the ID of the card, or at least it's representation to the system, without having to get his hands dirty with disabling kext signing.

I also had this idea and recently had a look at the fimware updater for the SAMSUNG 840 EVO. unfortunately the firmware image seems to be compressed or encoded in some way. I couldn't find any references for "SAMSUNG" or "840" or "EVO". I gave up after a few minutes. but maybe somebody with more knowledge about firmwares could figure it out..?

all that is needed is that an SSD identifies itself as "APPLE SSD XXXXXX" and the problem would be solved...

 

[m4v3r1ck]

Boot to Mavericks with Trim enabled.

Mount the Yosemite file system

Open disk utility and select the Yosemite partition

Click the repair disk function

Watch the progress on the log window

Notice at the end of the log, it reports "Trimming unused blocks"

Realize that trim is working, otherwise it couldn't "Trim Unusd Blocks"

Great info's!

Thanks

 

[flowrider]

all that is needed is that an SSD identifies itself as "APPLE SSD XXXXXX" and the problem would be solved...

Not really. Once you started mucking with the device id (even if you could change it) you'd be locked out of firmware updates. The RIGHT way to solve the problem is for Apple to stop this kext BS. They know what the after market is for components that are designed for or work correctly in a Mac. I really can't understand their attitude on this. I have two Solo x2s with Samsung SSDs in my 5,1 Mac Pro and a Transcend SSD in my MBA.

Lou