Sandforce Drives and TRIM
How well do you think TRIM works on a SandForce drive?
Thats right not at all. Without a format of the drive there will be no recovery by TRIM
source: Anand Tech
i noticed this. the drive has to be already written to 100% of LBAs with totally incompressible data, then written to with more incompressible data. but yes for it to 'panic lock' in that manner is interesting. an extreme corner case, but still possible...im wondering if the SF controller requires more 'room' to trim incompressible data than provided by the OP? very strange, but this only manifests itself when the drive is 100 percent full.
What i wonder if it does this when it is utilizing RAISE and its extra OP.
that's actually 100% right on target there, Bill. I've backed my drive into that same corner more than several times in the past. The funny thing is that he needed to go to the trouble of filling it up first. I did not.
question how did you go from 15gb to 19gb the very next run?
there was a bit of an issue with me overclock it appears. LOL
It went like this. I nearly finished the 9 x 4000MB run and saw nearly the same 112MB/s(actually 115MB/s IIRC) write speed as posted in the above 1 x 1000MB test run. I crashed.. I cussed.. I rebooted.. I immediately reran a quick 1 x 1000MB test to verify that I was indeed still at that 11xMB/s throttled speed. It obviously was.
Then after the next series of 9 x 4000MB test runs, I realized that the CDM test file(CDM3 Temp file actually scratched to the drive being tested) of 4000MB was actually still there from the prior crash. I later deleted it when I saw the size discrepency. No trickery involved.. just partial stupidity and plain old ignorance are my only excuses. LOL
no accusation whatsoever that makes perfect sense just curious
im wondering if this isnt actually the sign of LTT kicking in, and anand just isnt familiar with the throttling. maybe filling the device with data propagates an instant lifetime throttling, instead of going off of the write rate.
that makes a whole lot of sense. i bet your right
the sf don't trim until it runs out of 'fresh' nand.
Last edited by m.oreilly; 07-Feb-12 at 11:33 PM.
more precisely.. they send trim to mark deleted blocks immediately BUT choose to recover blocks on-the-fly ONLY when the drive has no fresh blocks remaining.
This is why the silly dodo's who test force-trims on these drives are incorrectly lead to believe that recovery has occured because they have forced the same amount of space trimmed?.. to be immediately recovered by the controller as most others on the market will do in near immediate fashion. When in essence, they have only succeeded in writing to all the remainder of the free space availble on the already struggling drive by writing that data needed to force the trim. They have literally forced their drive into initiating its much more aggressive on-the-fly recovery algorithm by pushing it over the edge with even more writes.
I've said it before.. and I'll say it again.. you CANNOT force-trim a performance degraded Sandforce drive back to fresh speeds(or even near fresh for that matter). You can however, beat the snot out of it with even more data and force it into more aggressive immediate recovery mode. Or.. do as some of the "extreme usres" do and let GC do that and so much more in idle time. Such as... deleted data/block recovery(trim or no-trim).. partial block consolidation.. and even static data rotation to keep wear leveling in tip-top shape.
If you're really extreme(apparently my usage is considered to be enterprise by some standards)?.. add some additional manual OP to the mix for even better results. Here's a newer review comparing OP on the 520 and the Vertex 3 which just goes to show that the testers are finally starting to figure stuff out that has been known by others for quite some time now. Better late then never, I guess. lol
Intel SSD 520 Enterprise Review | StorageReview.com - Storage Reviews