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Does Snow Leopard support the *critical* SSD "TRIM" command?
- Thread starter winterspan
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Mr KnowItAll
I love how Mr KnowItAll there is banging on about TRIM being to do with the file system.
It has NOTHING to do with the file system.
TRIM is a controller command and it is drivers that speak to the controller... the file system is completely and utterly abstracted from it. It will be up to the ATA drivers to adapt to the presence of an SSD supporting TRIM so that when format and delete commands come down from the higher levels they are carried out appropriately.
Apple is currently supplying Samsung PB22-J 128GB and 256GB SSDs. These should also receive a firmware update to enable TRIM in the controller. For the moment that is expected to be closer to the Windows 7 launch and when the powers-that-be ratify TRIM into the ATA standard. That is expected soon.
Apple already provides "TRIM" support in the iPhone and iPod touch. I put it in quotes because it is essentially 'draft' TRIM support. Leopard does not support TRIM and that is not expected to change.
There is nothing public about Snow Leopard's ATA drivers supporting TRIM but be aware that owing to its presence in the iPhone and iPod touch you can undoubtedly assume it is well known to Apple. As Snow Leopard is shortly to be released it won't be long before this particular detail is public knowledge.
I love how Mr KnowItAll there is banging on about TRIM being to do with the file system.
It has NOTHING to do with the file system.
TRIM is a controller command and it is drivers that speak to the controller... the file system is completely and utterly abstracted from it. It will be up to the ATA drivers to adapt to the presence of an SSD supporting TRIM so that when format and delete commands come down from the higher levels they are carried out appropriately.
Apple is currently supplying Samsung PB22-J 128GB and 256GB SSDs. These should also receive a firmware update to enable TRIM in the controller. For the moment that is expected to be closer to the Windows 7 launch and when the powers-that-be ratify TRIM into the ATA standard. That is expected soon.
Apple already provides "TRIM" support in the iPhone and iPod touch. I put it in quotes because it is essentially 'draft' TRIM support. Leopard does not support TRIM and that is not expected to change.
There is nothing public about Snow Leopard's ATA drivers supporting TRIM but be aware that owing to its presence in the iPhone and iPod touch you can undoubtedly assume it is well known to Apple. As Snow Leopard is shortly to be released it won't be long before this particular detail is public knowledge.
wipe command for a Macbook Air
I've noticed my Macbook air (2nd Gen; 120GB SSD) slow down a fair amount since I first bought it (have not run benchmarks). Is there a wiper utility I could safely use from bootcamp? (I mount my Mac HD in the Windows OS using MacDrive).
Promising to hear there may be TRIM support implemented for 10.6
I've noticed my Macbook air (2nd Gen; 120GB SSD) slow down a fair amount since I first bought it (have not run benchmarks). Is there a wiper utility I could safely use from bootcamp? (I mount my Mac HD in the Windows OS using MacDrive).
Promising to hear there may be TRIM support implemented for 10.6
Security may be > than lifespan, but on an SSD secure delete doesn't help you much. Secure delete works by addressing each specific sector of a disk where data is reported as being located, and overwriting those bits. But SSDs don't store data sequentially the way hard drives do (this allows them to get performance gains by having multiple controllers accessing data simultaneously -- almost like a mini RAID array). As a result, on an SSD the "physical locations" on the file system are virtual and data is written to the underlying physical memory round robin. This means running secure delete results in zeroes being written to the disk that are the same length as the file being deleted...but it can't be guaranteed they're written in the same location that the data was written in the first place.
Secure delete is little more than a nuisance that slows your drive down -- similar to defragmentation tools. To truly secure delete a file on an SSD, you'd need to write zeroes to the entire "free space" at least once without freeing up any of the "space" they take up...which, as you can guess, is gonna result in a very slow drive when you're done. Indeed, when I want to test SSDs for their "mid life" performance, I start by securely erasing the whole drive. The result is the same as if I'd filled the drive with data and deleted it all.
Besides -- with SSDs, once data from the flash ram, it's gone for good. There's no issue of transient images of the data like there is with magnetic drives. Real security on an SSD should mean encryption, and don't worry about deletes.
Unless they fix TRIM support for OS X and Bootcamp ill have to switch to a Sony Vaio. Apple used to think of everything and fix things 100%, but lately they changed completely. It has reached the point where PCs are almost easier to own. Apple releasing EFI upgrades that actually makes your computer not work at all / not work as good. This haven't even been addressed with a press release and even less a fix, and it been going on for a few months? Also, not supporting TRIM will make it so people with OS X are actually BEHIND in the technological progress, you cannot use SSDs, which any PC will be able to do.
As stated earlier, TRIM is in the ATA spec and is something on hardwarelevel. It's between the ssd and the controller. Filesystems have nothing to do with it, aka it's filesystem independent. However, it does have everything to do with the OS because the OS needs to have TRIM support which Win7 and Linux do (it seems that OS X also has something like TRIM support). Just make sure that whatever you use as a filesystem can be used in Windows 7/Linux or else it won't trigger TRIM.
In other words: as long as you have Win7 and an SSD that support TRIM it'll do TRIM regardless of whatever filesystem you put on it just as long as Windows can use it (that means NTFS and FAT32).
@ Davidkoh: why do you need TRIM that much? SSD's have a nice feature called garbage collection and the Indilinx drives will get an even better version of that garbage collection (it's a lot faster) combined with TRIM (the OS triggers TRIM, TRIM should trigger the garbage collection and make sure both do its magic). I don't think it will be a big problem if Snow Leopard does not support TRIM after all, the garbage collection will be enough. You can use SSD just fine, even at this moment without any TRIM support (because that's where we stand right now: there is no TRIM, only garbage collection). If you take a look at the Indilinx Barefoot drives you'll see they have enormous amounts of problems when using TRIM. There are some problems triggering TRIM at the moment you hibernate the machine, this will create dataloss. Other SSD's manufacturers also have problems with the TRIM implementation. TRIM is not really a good option right now, it is far too buggy and will cause dataloss so using TRIM would be a set back in technological progress.
TRIM does use the filesystem indirectly. It uses the filesystem to know which blocks contains deleted information. Every time you delete something what you essentially do is delete the "map" to that file from the filesystem. The OS will then send a TRIM command to the drive. The TRIM function keeps track of which blocks are empty (no data in) and deleted (data no longer needed) and different implementations will then take different actions.
Garbage Collection will always be held back by not exactly knowing what is deleted and not, it can never be as effective. Also we really got no idea on how much the life of the drive is lowered by using a Garbage Collection function, since it is moving files around there is essentially a lot of extra writes to the cells.
Indilinx problems with dataloss have nothing to do with TRIM as a function in itself, it is a product of poorly written firmware by Indilinx. Good to note is that Indilinx seem to have have next to no internal testing, they seem to send it out to manufacturers using their controller and in some cases these let the customers test the firmware for bugs.
Advice needed
Ok. I've been ogling SSD's for a while now. I was all set on the Corsair 256 until I read the Anandtech article. TRIM appears to be a major deal, performance wise. Will somebody please just tell me what to buy? The fan noise from running a 7.2k WD on my 06 MBP is sending me mental. Performance isn't a big issue for me, but I don't want to waste money by buying based on "new" specs that degrade overnight.
Will somebody be kind enough to make the decision for me? 160gb is adequate.
Thank you all.
Ok. I've been ogling SSD's for a while now. I was all set on the Corsair 256 until I read the Anandtech article. TRIM appears to be a major deal, performance wise. Will somebody please just tell me what to buy? The fan noise from running a 7.2k WD on my 06 MBP is sending me mental. Performance isn't a big issue for me, but I don't want to waste money by buying based on "new" specs that degrade overnight.
Will somebody be kind enough to make the decision for me? 160gb is adequate.
Thank you all.
I have a Corsair P128 in my 13" MBP. Great drive for the money (Paid $300 after rebate a few months ago).
Does anybody know...
if I leave free, lets say 30gb in my ssd of a whole of 160gb, will this prevent my ssd disk from corruption or slow performance due to the lack of support of trim command?
It would be good to know about this, until apple decide to provide trim support.
if I leave free, lets say 30gb in my ssd of a whole of 160gb, will this prevent my ssd disk from corruption or slow performance due to the lack of support of trim command?
It would be good to know about this, until apple decide to provide trim support.
Fusion 3 is an emulator, it creates a VM, it has nothing to do with a real windows 7 installation. Therefore you can't use TRIM and if it was possible, you could damage your mac partition. There is nothing to gain from that.
As long as SL doesn't support Trim, it's a not go.
As long as SL doesn't support Trim, it's a not go.
@cool11: If you make your hard drive partition smaller than actual disk size, you would solve the problem (almost i think). read the anandtech article for more information.
But if you buy an Intel x25-m you won´t need this i think, because it doesn´t degrade that much. Again, read the anandtech article
But if you buy an Intel x25-m you won´t need this i think, because it doesn´t degrade that much. Again, read the anandtech article
You might want to do some more research and read very carefully what you are typing as you've already proved you're wrong about TRIM having to do with the filesystem
TRIM like GC has got nothing to do with the file system whatsoever. It has everything to do with the OS. If the OS issues a delete command for files/dirs it will normally remove the links to the inodes so there is no reference to it any more in the OS/filesystem. It does not remove the data physically. TRIM is what makes the OS communicate with the ssd to have the data removed physically. The OS will do 2 things when TRIM is supported: it will remove files/dirs the normal way AND it issues TRIM so it will also be deleted physically. Just like you explained in your story: it is the OS that is triggering TRIM, not the filesystem!
Indilinx/OCZ explained the feature as being triggered whenever you empty the trash, which is what it does exactly. Upon a normal delete Windows moves stuff to the trash which is just a change in the filesystem. When emptying the trash it will remove the link in the filesystem pointing at the physical data. In case of TRIM it will also issue TRIM so the ssd will remove the physical data in order to regain performance.
TRIM has got nothing to do with the filesystem and TRIM does not remember anything. It's just a command the OS can give to the controller/ssd so the ssd will remove certain memory cells. If it were to have filesystem support it would need to know about all of those filesystems and would need to read it actively. This is unwanted behaviour as it causes a massive problem called dataloss. It being in the ATA spec should have given a biiiiig hint it's not about filesystems
It was a bug in the TRIM implementation by Indilinx and they have fixed that bug by rewriting the entire firmware. TRIM got triggered at the wrong time when hibernating causing dataloss which is exactly what I explained in my post. Seemed clear to me that this would refer to a bug in the implementation and not a bug in TRIM itself.
@alexrydz: if you want TRIM right now forget it. Only OCZ Vertex drives (and those other Indilinx Barefoot drives) support TRIM. Next you'll need a chipset (with driver) supporting TRIM and an OS supporting TRIM (which would mean Win7). If you miss one part in that equation TRIM won't work. The various GC implementations in the world make ssd's retain their performance quite well. If you look at the Intel X25-m you can see that these ssd's are the best at doing this. Next are the Indilinx Barefoot drives like the OCZ Vertex. Others may follow or may not be so good at it.
@Emil Jan: no, as this would be pointless because the hard disk of any vm is just a file on the drive (virtualised hard disk!). It's no different from a document, picture, etc. It's still up to OS X to trigger TRIM (which it can't atm).
I would love to see TRIM get added to OSX, but at the rate of SSD development, I will probably just jump ship to the newer SSDs when I see big performance hits. Right now all of my SSDs are screamers, however I do put most of the highly repetitive writes on HDDs.
Here's my thinking. TRIM isn't just some OS command. The firmware of the drive also needs to support it. I'm guessing most of Apple's current SSDs don't support and most likely will not gain support for it. Flashing the firmware of an SSD typically means wiping out the SSD. I bet TRIM support is coming, but not until Apple releases laptops with SSDs that support it. Maybe next update, maybe not.