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All Solid State Drives Suffer Performance Drop-off
Lucas123 writes "The recent revelation that Intel's consumer X25-M solid state drive had a firmware bug that drastically affected its performance led Computerworld to question whether all SSDs can suffer performance degradation due to fragmentation issues. It seems vendors are well aware that the specifications they list on drive packaging represent burst speeds when only sequential writes are being recorded, but after use performance drops markedly over time. The drives with better controllers tend to level out, but others appear to be able to suffer performance problems. Still not fully baked are benchmarking standards that are expected out later this year from several industry organizations that will eventually compel manufacturers to list actual performance with regard to sequential and random reads and writes as well as the drive's expected lifespan under typical conditions."
Even the article itself says that it isn't much of a big deal, once you get past the headline, of course.
And this seems like the sort of issue that will be resolved in the next generation, anyway.
This isn't a bug, it is a property of flash memory. That is like calling a car that eventually runs out of gas poorly designed. The only way around it would be a new type of "defrag" where unused blocks were cleared in advance and partially used blocks consolidated.
"Drastically effected its performance"
This is patently false. Whats really happening is that SUSTAINED WRITE PERFORMANCE decreases by about 20% on a full drive as compared to a fresh drive. You might say 20% is too much, and I'd probably agree with you, except that ONLY sustained write performance is being affected.
Your read speed will not decrease. Your read latency will not increase. Unless you're using your SSDs as the temp drive for a high definition video operation (And why the hell would you for that? Platter drives are far better suited to that task between sequential write speed and total storage space) then you have nothing to worry about.
This happens on all drives, as the article title correctly states. The solution is a new write command that pre-erases blocks as you use them, so the odds that you have to erase-then-write as you go along are decreased. Win7 knows how to do this.
Nonetheless, it is totally overblown and your SSD will perform better than any platter based drive even when totally full.
http://www.anandtech.com/storage/showdoc.aspx?i=3531&p=4
Anandtech has a very detailed article that explains all about this and some ways to recover the lost speed (sometimes).
-Lod
Think I'll stick with the tried and true IDE/SATA tech.
Psst: SSD drives connect via SATA.
Game! - Where the stick is mightier than the sword!
Can a fail be insightful?
The fundamental problem with NAND-based solid-state drives is that they use NAND flash memory--the same stuff that you find in USB flash drives, media cards, etc.
The advantages of NAND is that NAND is both ubiquitous and cheap. There are scads of vendors who already make flash-memory products, and all they need to do to make SSDs are to slap together a PCB with some NAND chips, a SATA 3Gb/s interface, a controller (usually incorporating some sort of wear-leveling algorithm) and a bit of cache.
The disadvantages of NAND include limited read/write cycles (typically ~10K for multi-level cell drives) and the fact that writing new data to a block involves copying the whole block to cache, erasing it, modifying it in cache, and rewriting it.
This isn't a problem if you're writing to blank sectors. But if you're writing, say, 4KB of data to a 512KB block that previously contained part of a larger file, you have to copy the whole 512KB block to cache, edit it to include the 4KB of data, erase the block, and rewrite it from cache. Multiply this by a large sequence of random writes, and of course you'll see some slowdown.
SSDs will always have this problem to some degree as long as they use the same NAND flash architecture as any other flash media. For SSDs to really effectively compete with magnetic media they need to start from scratch.
Of course, then we wouldn't have the SSD explosion we see today, which is made possible by the low cost and high availability of NAND flash chips.
...you mean to tell me that fragmentation *reduces* the performance of storage???
Fragmentation on hard disks reduces performance because of the time it takes to physically move the disk heads around. There are no physical heads to be moved around in SSDs, therefore it's perfectly reasonable to assume that that mechanism of performance hit will not occur on SSDs, and therefore it's not an issue. I did a small test years ago on the effects of flash memory fragmentation in a PDA, and I, and most people I discussed the matter with seemed to be quite surprised with the results at the time. I never got a good technical explanation of why the performance hit was so large. Doubt that's the same mechanism at work as with modern SSDs, but sort of relevant anyway.
Oh no... it's the future.
The reason the performance hit is large is because writing to SSDs is done in blocks. Fragmentation causes part-blocks to be used. When this happens, the SSD must read the block, combine the already-present data with the data it's writing and write the block back, rather than just overwriting the block. That's slow.
Intel has solved theirs about 95%, but they are helped by their write speeds being limited to 80 MB/sec. With the new firmware, it is *very* hard to get an X25-E to drop below its rated write speed.
http://www.pcper.com/article.php?aid=691&type=expert&pid=5
OCZ has not yet solved it. They currently rely on TRIM, and in my testing that alone is not sufficient to correct the fragmentation buildup. IOPS falls off in this condition as well.
Allyn Malventano
Storage Editor, PC Perspective
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Uh, not really. You need to test real usage conditions. The most common hard-drive (ab)using applications are going to be databases, development (edit, save, compile, rebuild; uses lots of disk access), and work-horse applications like VMware, Photoshop, Video editing software, 3D rendering, etc.
Especially things like SQLite which really tends to hammer the drives and is embedded in lots of applications.
I have some experience with SSD's on development machines and database servers. I speak from experience when I say they are much less reliable than the old spinning hard-drives when used in those environments. In fact, I have never seen a single one last more than a year.
Looks like it. they're all borked. Every single one of them. I said so in the title, and I only bother reading the title in Slashdot stories these days.
http://4onlineshop.stores.yahoo.net/an5insax1ram.html
The ANS9010 and 9010B suffer no such issues since they are ram-based. They also have a CF backup slot in addition to a backup battery. Very slick and a better solution for a boot drive than a typical SSD if you absolutely must have maximum speed. Pricing with RAM is comparable to an enterprise-level SSD, just roughly 1/2 to 1/4 the capacity is all.
Correction to my last. I was speaking of X25-M, not E.
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