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You will all stop the personal attacks or be banned.
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Yes, the sequential IO speeds will usually be faster in RAID than with a single bigger SSD.
But the thing is, most people do not need sequential speeds in excess of 400MB/s read, and in fact will not notice the difference in everyday usage.
What most people WILL notice is the hassle of dealing with a RAID-0 volume as compared to a single large SSD. In addition, the RAID-0 volume will be a lot more likely to fail and lose data than the single large SSD.
So, as I wrote before, unless the OP has a specific need for the performance of the RAID-0 volume of SSDs, he will probably have a better experience with a single large SSD.
the area where it will help a lot is in backups. everyone on a single drive should be backing up their volume, and with a raid0, the backup becomes much faster since it will actually utilize the seqential or a higher qd that the raid0 will be capable of.
You should not say always. There are some SSDs that perform significantly worse when no pages are marked invalid. For example, look at tweaktown's reviews, where you can see that the 75% full bar (light purple) is less than half of the "empty but dirty" bar (green) for a number of the SSDs that they have tested. They do not have a 100% full bar, but that would be significantly lower than the 75% full bar for many SSDs. And without TRIM, the drive will eventually be operating at 100% full all the time, even if you are currently only using a small amount of the RAID 0 space.
http://www.tweaktown.com/reviews/4179/corsair_force_3_120gb_solid_state_drive_review/index10.html
Once all the LBAs have been written at least once, the drive is basically full, even if the filesystem on the SSD contains no files.
I think you missed my point, since that is all irrelevant. I only claimed that "always" was incorrect. All it takes is a single counter-example.
Additionally, your computation is incorrect, since you used 75% when you really need to use 100% (i.e., disable TRIM, fill up the drive 100%, delete the files, then run the test) which unfortunately, tweaktown does not measure.
the gap from 25 to 75 wasn't that big. I can't imagine the gap from 75 to 100 is that much more substantial.
Well, it seems you need a better imagination. There is a reason the enterprise SSDs reserve a lot more space than 7% like the consumer SSDs. That last 10 or 20% can make a difference.
Besides, AGAIN, it is irrelevant to my point, which is that ALWAYS is incorrect.
so far that article does nothing to support a scenario where the solo drive with the same data beats out the raid array. at no point did their score ever go below 50% of the fully clean drive even. if you have actual data for a raid array that was filled 100%, emptied, and garbage collected, and somehow still performed less than a solo drive, post away.
Please try to follow the simple logic:
1) On several of the SSDs, the 75% full benchmark was less than half the speed of the dirty/empty benchmark
2) Without TRIM, a used SSD will eventually behave as 100% full (which is slower than 75% full) even if the filesystem is empty
3) Therefore, when the filesystem is empty, some of the SSDs will have used performance (100% full, no TRIM) less than 50% of the empty / dirty with TRIM performance
4) A RAID-0 of two used SSDs with less than 50% performance of an empty / dirty TRIMmed SSD will bench slower than a single empty SSD with TRIM (and likely even slower than the equivalent double-capacity SSD)
5) A RAID-0 is NOT always faster than a single SSD
for the dirty/empty, they've given no indication they allowed the drive to trim.
) On several of the SSDs, the 75% full benchmark was less than half the speed of the dirty/empty benchmark
2) Without TRIM, a used SSD will eventually behave as 100% full (which is slower than 75% full) even if the filesystem is empty
3) Therefore, when the filesystem is empty, some of the SSDs will have used performance (100% full, no TRIM) less than 50% of the empty / dirty with TRIM performance
here is the deal, you are trying to compare the performance from a empty but dirty drive, to a drive being full. that is irrelevant in the argument that raid is slower than a single device. You are assuming that a user would even use a SSD totally blank.
No, that is not what I am assuming. What I am assuming is that SSDs work the way they work with and without TRIM.
here is the main issue that I see here:
too much assumption. You are stating something as fact, that has not been proven. you have no reliable data to back up your claims.
I'm not sure what you mean by "allowed the drive to TRIM".
The TRIM commands were sent to the SSD. They describe the procedure in depth in the article they link to about their methodology for that test. dirty / empty is TRIMmed (they delete the data and empty the trash under Win7)
I read that link before I posted. I ctrl+f'd for trim on all 7 pages... it wasn't there. they really don't give indication that the drive was trimmed at all but I guess we are supposed to assume that since they are on windows 7
No, I am making minimal assumptions......
Try to follow the simple logic. A claim was made that RAID-0 of two SSDs was always faster than a single larger SSD with TRIM.
I linked to data, and used simple reasoning, to show a counter example where RAID-0 of two SSDs would not be faster than a single SSD with TRIM.
Therefore, RAID-0 of two SSDs is NOT always faster than a single SSD with TRIM.
Please try to think about this and understand the basic logic. No need to post more nonsense arguments with bogus assumptions.
No, I am making minimal assumptions.
Try to follow the simple logic. A claim was made that RAID-0 of two SSDs was always faster than a single larger SSD with TRIM.
I linked to data, and used simple reasoning, to show a counter example where RAID-0 of two SSDs would not be faster than a single SSD with TRIM.
Therefore, RAID-0 of two SSDs is NOT always faster than a single SSD with TRIM.
Please try to think about this and understand the basic logic. No need to post more nonsense arguments with bogus assumptions.
Besides, the data makes no sense if there was no TRIM. After filling it up to 75%, how could the benchmark get much faster after deleting the files, unless there was TRIM or secure erase (and they would certainly not call a SE'd SSD "empty / dirty")? Just deleting files without TRIM or SE, the SSD does not know that the sectors have been freed -- the SSD would still have the pages corresponding to at least 75% of the LBAs marked as valid, despite the files being deleted. Unless they were TRIMmed, which they obviously were.
the same way the agility 3 is somehow faster at 75% full compared to 50% full... or how the corsair force 3 is faster after being marked dirty/empty than in its initial clean state.
if someone asks me if they should get a raid array or stick with a solo drive for trim, I'm going to ask them if they plan to fill their drive to 25% of its capacity. and when they say yes, recommend the raid assuming they have a controller to handle it
However, the big question is how much faster, and whether it is worth the hassle of RAID and the increased chance of a failure with two SSDs.
You are looking at differences of a few percent, which are in the noise. I am talking about differences of around 50%. Big difference.
However, the big question is how much faster, and whether it is worth the hassle of RAID and the increased chance of a failure with two SSDs.
so.. who wants to run the test
i have tons of SSD, but they all are matching sizes.