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  #1  
Old 08-21-2011, 03:28 PM
Sudjaino Sudjaino is offline
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Default Sandforce & Garbage Collection

I know Sandforce controller trims directly when we empty recycle bin, and does garbage collection when writing new data on the same blocks, which apparently causes a slowdown. My question is simple: Is there any way (or utility) to force the drive to do complete cleaning of free space (garbage collection) on demand , ex. after we delete a huge amount of data ?
I suppose Perfectdisk (latest version) & Diskeeper Hyperfast does exactly this on SSD (which is called free space consolidation)?
If yes, is there any other alternative that is free ?
Thanks
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  #2  
Old 08-21-2011, 03:44 PM
scorpionri scorpionri is offline
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There's no way to trigger the block recycling on SF drives ( actually there is one ... secure erase, but that will basically clear your entire drive and not just the blocks that were "trimmed" ).
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Old 08-22-2011, 04:23 AM
ssd_noob ssd_noob is offline
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I don't think free space consolidation is the same as garbage collection. In fact they are 2 quite different things.
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Old 08-22-2011, 02:03 PM
Bleupomme Bleupomme is offline
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There is sdelete -c from sysinternals. But I would not do it on a regular basis.

Manu
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  #5  
Old 08-23-2011, 02:06 AM
Serville Serville is offline
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What I read so far indicates that something like garbage collection is done by Sandforce controller when it writes data back to the deleted/trimmed blocks, which is why the writing performance could be affected a lot because it has to write off/move the deleted data before the new data could be written over them.

I thought Hyperfast did the "garbage collection" ahead of time, but I think I'm also wrong, because I remember reading that the process of GC inside Sandforce is executed internally by the controller itself. No utility can pass the command on demand. So, how/what does Hyperfast actually do to maintain top performance of SSD drive ?

The only description from Diskeeper about Hyperfast is :
"HyperFast creates and maintains optimized free space, increasing the controller’s ability to write sequentially and thereby enormously increasing the peak speed and life of the SSD. "

If I understand correctly, it seems "Secure erasing" is the only way to restore performance back quickly. But frequent "secure erasing" certainly reduces SSD life a lot because it has to write each block. If I have a 60GB SSD, a process of secure erasing the drive will also mean "writing 60GB of data to the SSD". I know because I've done it a couple of times to my 60GB drive, and SSDLife reported exactly a 55GB write to the SSD after secure erasing. Coupled with restoring a 20GB image backup to the drive, that could mean a 90-100GB of written data in just 15 minutes. OMG !

A sticky recommending a "secure erase" for quick performance recovery FAILS to warn users about this important fact.
The warning should have been made because it substantially reduces SSD life

Last edited by Serville; 08-23-2011 at 02:28 AM.
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Old 08-23-2011, 02:14 AM
scorpionri scorpionri is offline
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Then only drives that allowed you to trigger the garbage collector were the Indilinx Barefoot ones, the G2 Intels ( and perhaps newer Intels as well ). This was mainly a feature used in non-TRIM OSes to help the drives maintain top performance. Currently there is no way to force the GC on a SandForce drive as it's FW will decide when and how to do that.
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Old 08-23-2011, 02:48 AM
ssd_noob ssd_noob is offline
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Quote:
Originally Posted by Serville View Post
A sticky recommending a "secure erase" for quick performance recovery FAILS to warn users about this important fact.
The warning should have been made because it substantially reduces SSD life
There's an experiment going on at Extreme Systems to see how many wrties a 64GB SSD can endure before it completely fails. Roughly, for almost any brand, it would be at least over 400TB, or 100GB writes every single day for over 10 years. I don't think a normal user has anything to worry about where the life of the SSD is concerned unless he deals mainly in photo/video editing.
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Old 08-24-2011, 04:13 PM
Quietman Quietman is offline
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Quote:
Originally Posted by Serville View Post
If I understand correctly, it seems "Secure erasing" is the only way to restore performance back quickly. But frequent "secure erasing" certainly reduces SSD life a lot because it has to write each block. If I have a 60GB SSD, a process of secure erasing the drive will also mean "writing 60GB of data to the SSD". I know because I've done it a couple of times to my 60GB drive, and SSDLife reported exactly a 55GB write to the SSD after secure erasing. Coupled with restoring a 20GB image backup to the drive, that could mean a 90-100GB of written data in just 15 minutes. OMG !
I did a secure erase on my Force 3 120GB after upgrading the firmware to v1.3 using the suggested pmagic utility and it took less than 2 seconds.

The SSD had an updated Windows 7 install on it, must have been around 30GB used. Surely it could not have zeroed over that used space in such a short time? Whatever it did do worked, the drive was empty.
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  #9  
Old 08-24-2011, 05:04 PM
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Yellowbeard Yellowbeard is offline
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Quote:
Originally Posted by Quietman View Post
Surely it could not have zeroed over that used space in such a short time?
Actually yes, it does.

Also, just for general info in this thread, my understanding is that you can trigger the SandForce drives to do their GC by deleting a file and then emptying the Recycle Bin. Do this and leave your computer idle and the drives will do their magic.
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Old 08-26-2011, 03:59 AM
Serville Serville is offline
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Strange. Everbody say the secure erase only took 2-3 secs, but it took about 5 minutes for me I think. It's about 2-3 secs for every 1%. I follow exactly the same instructions. The only difference is the version of partedmagic I use which is 5.7. I wonder why.
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Old 08-26-2011, 05:43 AM
_Anvil_ _Anvil_ is offline
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Quote:
Originally Posted by Serville View Post
Strange. Everbody say the secure erase only took 2-3 secs, but it took about 5 minutes for me I think. It's about 2-3 secs for every 1%. I follow exactly the same instructions. The only difference is the version of partedmagic I use which is 5.7. I wonder why.
I'm quite sure you are using the wrong tool for the task.

A Secure Erase using the correct tool (HDDerase or equivalent) takes 2-3 seconds.
Some tools perform other tasks while cleaning and they are not "compatible" with SE for SSD's. (puts extra wear on the drive)

Having said that, a Quick-Format is sufficient in most cases.
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