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Why You Need TRIM For Your SSD

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proxess 4th February 2010, 10:23 Quote
So how exactly to I reduce performance degradation on my Eee's teeny SSD?
DarkFear 4th February 2010, 10:39 Quote
So this means I have to switch to Win 7 if I plan on getting a SSD in the not too distant future? Or is there any way to get Win 7 TRIM running in Vista?
Aracos 4th February 2010, 10:45 Quote
Quote:
This update also brings the first garbage collection algorithm for Indilinx based drives, providing performance recovery in non-TRIM operating systems like Linux, XP and Vista
I thought TRIM was supported in Linux kernal 2.6.28 and up as long as you're using a TRIM supported filesystem such as EXT4?

EDIT: nvm but there is wiper.sh ;)

EDIT AGAIN: How does trim work? Is it filesystem dependant? For example you have 2 NTFS partitions and one ext4 partition, would Windows 7 use the trim command and then the controller would trim the entire drive? Or is it just the partitions it see's? I have no idea how trim works ^_^
Jamie 4th February 2010, 11:05 Quote
I was going to ask a similar thing to storm20200. Does file system have any effect on TRIM or the degradation of the SSD performance? What about other Operating systems such as Linux / OSX?
Baz 4th February 2010, 11:21 Quote
Quote:
Originally Posted by Jamie
I was going to ask a similar thing to storm20200. Does file system have any effect on TRIM or the degradation of the SSD performance? What about other Operating systems such as Linux / OSX?

Trim is only supported in Win7 with NTFS atm to my knowledge - all other OS or file systems you're limited to the drive's onboard performance degradation algorithms - both the Indilinx and Samsung based drives now support this, although i've not done any significant testing using them - from what i've seen they're not as effective as trim. To my knowledge the Intel ones don't pack any garbage collection algorithms and are designed specifically for trim to keep them in shape.
Baz 4th February 2010, 11:28 Quote
Quote:
Originally Posted by storm20200
How does trim work? Is it filesystem dependant? For example you have 2 NTFS partitions and one ext4 partition, would Windows 7 use the trim command and then the controller would trim the entire drive? Or is it just the partitions it see's? I have no idea how trim works ^_^

Trim works by telling the drive to discard the junk data once you've deleted it - it moves the contents of the cell into the cache, scrubs the junk data and then rewrites the contents with the junk space now allocated as free - think of it like permanently deleting the file. This also allows the now free space to be allocated to the drive's array of free blocks to be written to.

SSDs shouldn't care about how they're partitioned as they wear level across all the free cells on the drive anyway to evenly distribute write cycles, and as the trim command is performed in the controller and not in the OS (which only triggers the trim command) I don't see why trim wouldn't work across multiple partitions on a drive - you'd need an NTFS partition running Windows 7 in order to trigger it though.
Hugo 4th February 2010, 11:38 Quote
How does this work with the "Previous Versions" function in Windows? AFAIK that works precisely because data isn't actually deleted when you hit delete - presumably TRIM eliminates this capability?
MeanGreeny 4th February 2010, 12:00 Quote
Can we roughly equate the Crucial M225 performance to any of the SSDs in this report ? [since it now also has TRIM support]

The M225 prices have come down a lot recently and are at a more attractive price than the equivalent [in GB] OCZs
Baz 4th February 2010, 12:02 Quote
Quote:
Originally Posted by HugoB
How does this work with the "Previous Versions" function in Windows? AFAIK that works precisely because data isn't actually deleted when you hit delete - presumably TRIM eliminates this capability?

Trim is triggered when you empty the recycle bin, which perma-deletes information anyway (well, unless you get some data recovery apps out)- just hitting delete won't trigger it, so won't bork your data. Once you've emptied the recycle bin though, the file is properly gone.
phuzz 4th February 2010, 12:52 Quote
The Previous Versions functionality uses the Shadow Copy Service, which is making an actual copy of the data (well, everything that has changed). This copy is invisible to the user (and will show up as free space), but I'd assume that as far as the drive is concerned it's just more data.
afaik as your drive starts to run out of space, windows will start to delete shadow copies to leave space for more data.
Here is a good place to read a bit more on it, it's a pretty cool feature of windows imo.
Aracos 4th February 2010, 13:12 Quote
Quote:
Originally Posted by Baz
Quote:
Originally Posted by storm20200
How does trim work? Is it filesystem dependant? For example you have 2 NTFS partitions and one ext4 partition, would Windows 7 use the trim command and then the controller would trim the entire drive? Or is it just the partitions it see's? I have no idea how trim works ^_^
SSDs shouldn't care about how they're partitioned as they wear level across all the free cells on the drive anyway to evenly distribute write cycles, and as the trim command is performed in the controller and not in the OS (which only triggers the trim command) I don't see why trim wouldn't work across multiple partitions on a drive - you'd need an NTFS partition running Windows 7 in order to trigger it though.

So basically in theory if I was to have a NTFS patition with win7 on it then an ext4 partition and then a FAT32 partition, as long as I get windows 7 to trigger the trim command then it would trim they entire drive, that sounds alright ;)
Omnituens 4th February 2010, 14:16 Quote
Thanks for this, just in time, as about to buy 2 small vertex drives and raid them - I was not aware that TRIM does not work on raids.

Is this a temporary thing, or will trim NEVER work on raided drives?
Scootiep 4th February 2010, 15:06 Quote
I loved this review, thank you! I am currently coming away from this thinking (with the latest firmware updates) that the OCZ Vertex is the best bang for your buck drive for the average gamer out there. Does anyone feel otherwise or want to point me in the correct direction if I am wrong?
Phil Rhodes 4th February 2010, 15:10 Quote
No solution at all for XP people, then?
jrr 4th February 2010, 15:48 Quote
Do any drives effectively clean themselves up passively, without the process being invoked by the OS?
Baz 4th February 2010, 16:15 Quote
Quote:
Originally Posted by MeanGreeny
Can we roughly equate the Crucial M225 performance to any of the SSDs in this report ? [since it now also has TRIM support]

The M225 prices have come down a lot recently and are at a more attractive price than the equivalent [in GB] OCZs

Crucial M225 IS an OCZ Vertex 120 - Inside they're exactly the same hardware, just a different casing. The crucial is running v1916, the OCZ V1.5 - it's the same firmware, just named differently between the different partners. Good news for M225 customers!
Phil Rhodes 4th February 2010, 16:29 Quote
Well let me get this straight.

If I buy two M225s and put them in a RAID-0, they will decrease and decrease in speed until effectively unusable.

If I buy an M225 and use it under windows XP, it will decrease and decrease in speed until effectively unusable.

If I buy an M225 and use it under Vista, it will decrease and decrease in speed until effectively unusable.

If I buy an M225 and use it under Linux, unless I'm using the right combination of drivers, modules, configurations and other miscellaneous unix-style voodoo, it will decrease and decrease in speed until effectively unusable.

In each of these cases the three hundred quid device is then perma-bricked. So let me ask.

Are these things ever going to get fixed to the point where they actually work, in the general sense of work, which means they don't periodically require you stand on one leg in the rain performing a voodoo chant while casting bones and praying to the gods of technology? Can we have a simple bullet point list of the circumstances under which SSDs work, and circumstances under which they'll work for ten minutes then explode violently?

My confidence in buying any SSD has never been lower.
jrr 4th February 2010, 16:41 Quote
Phil: I'm pretty sure none of the cases involves perma-bricking.

I think we agree on the rest, though - I do not accept the new requirement of platform-specific maintenance software. I want these to work with an amount of upkeep similar to traditional hard drives - none at all. It seems like they could sacrifice a little bit of peak performance and make the drive keep itself clean *constantly* instead of performing it as a user-invoked software-controlled batch job.

I expect they'll get there soon.
Phil Rhodes 4th February 2010, 16:50 Quote
I don't think you can, at least with the approaches current TRIM commands seem to use. It relies on knowledge of what disk blocks represent data the OS might want, and what disk blocks contain true junk. The drive cannot ever know that; that's a filesystem thing, and that's the OS's job.

Forcing the drive to take notice of things the OS should deal with on its own is dangerous for quite a number of reasons.

P
jrr 4th February 2010, 17:04 Quote
Perhaps the solution involves a new filesystem that the drive can know more about.. I guess it won't happen as soon as I thought =\
Phil Rhodes 4th February 2010, 17:23 Quote
I think the solution involves drives that don't suck.
bogie170 4th February 2010, 17:35 Quote
Quote:
Originally Posted by MeanGreeny
Can we roughly equate the Crucial M225 performance to any of the SSDs in this report ? [since it now also has TRIM support]

The M225 prices have come down a lot recently and are at a more attractive price than the equivalent [in GB] OCZs

Heres my M225 with latest firmware and Trim enabled:

260 Mbs Read, 200 Mbs Write!

http://img.photobucket.com/albums/v710/bogie170/200Write-260ReadCrucialCT128-M225.png
Xen0phobiak 4th February 2010, 17:36 Quote
At the bottom of page three you say that the Kingston SSDNow M Series is Intel based. In the review that your link links to, you say it uses a samsung one.

Can you correct one of these please? I was/am considering the 64GB Kingston SSDNow M.

Thanks.
Omnituens 4th February 2010, 17:51 Quote
question: if i RAID'ed 2 drives, then imaged them, then every so often wipe, unraid, trim, re-raid and restore the image, would that be a long way round the "trim not working in raid"?
Baz 4th February 2010, 18:02 Quote
Quote:
Originally Posted by Phil Rhodes
Well let me get this straight.

If I buy two M225s and put them in a RAID-0, they will decrease and decrease in speed until effectively unusable.

If I buy an M225 and use it under windows XP, it will decrease and decrease in speed until effectively unusable.

If I buy an M225 and use it under Vista, it will decrease and decrease in speed until effectively unusable.

If I buy an M225 and use it under Linux, unless I'm using the right combination of drivers, modules, configurations and other miscellaneous unix-style voodoo, it will decrease and decrease in speed until effectively unusable.

In each of these cases the three hundred quid device is then perma-bricked. So let me ask.

Are these things ever going to get fixed to the point where they actually work, in the general sense of work, which means they don't periodically require you stand on one leg in the rain performing a voodoo chant while casting bones and praying to the gods of technology? Can we have a simple bullet point list of the circumstances under which SSDs work, and circumstances under which they'll work for ten minutes then explode violently?

My confidence in buying any SSD has never been lower.

Your assumptions, while typically alarmist, are wide of the mark. While you won't get trim on anything but Win 7 (which is bad) Indilinx drives still support an inbuilt garbage collection algorithm - I've just not had the opportunity to extensively test a firmware dependant update. Performance will not as you say, decrease and decrease in speed until effectively unusable - you won't brick the drive. The speeds we've seen here are absolute worst case scenarios - writing 1TB of data in just 1 day instead of the more reasonable one year, and even then with the Indilinx barefoot, didn't effect real world performance for things like booting Windows 7 at all.

Not using trim IS a major disadvantage, and drives will certainly suffer performance degradation but your continued scepticism is a little over the top. In the end though, you're right to be disappointed and those who want to run RAID 0 (not sure why considering it offers almost zero real world benefits), or older setups are left out in the cold. It's a tough situation, but SSDs are still what you'd regard as an emerging technology - it's why there's no "works with Windows 7" approval system for them yet. Bleeding edge tech always takes a few generations to get fully up to speed and work all the issues out - it doesn't mean it's redundant, or worthless in its current state.
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