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Roxor McOwnage

SSD's = Defrag is a thing of the past?

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They do a complete write, read, and md5 hash comparison. Currently, the el cheapo stick is at >20k cycles, and not a bit lost yet. Its getting a cycle every 6 minutes, so lets see when it will fail...
I have no doubts about a single stick surviving if it's lasted this long already, but I'd like to see someone do a test with a representative random sample-- say of at least 50.

We cycle at least 30 or so (possibly more, I'm not directly involved with this part of production much anymore) USB flash drives for our production work here and while theoretical failure rates say we shouldn't see any failures for something like 10 years in our little pool, in practice about one drive a month drops dead...

Granted our idea of standard use is worse than most people's entire lifetime of use. :)

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With a SSD that dies due to writing too much, it simply enters read-only mode and disallows writes. Long before that happens SMART will have alerts and warnings that any decent OS or RAID controller will detect.
That is what is supposed to happen. But I had an OCZ Core SSD that was silently failing on writes. The drive appeared to be working, but the OS would die from data corruption. I could only confirm what was happening by booting the a Ubuntu CD and running the linux program "badblocks" which will write the entire drive various patterns of bits and then read them back. Basically some of the bits were stuck as zeroes. When you tried to write a 1 to the bad bits, the drive would report successfully, but reading the bits back would show a zero.

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With a SSD that dies due to writing too much, it simply enters read-only mode and disallows writes. Long before that happens SMART will have alerts and warnings that any decent OS or RAID controller will detect.
That is what is supposed to happen. But I had an OCZ Core SSD that was silently failing on writes. The drive appeared to be working, but the OS would die from data corruption. I could only confirm what was happening by booting the a Ubuntu CD and running the linux program "badblocks" which will write the entire drive various patterns of bits and then read them back. Basically some of the bits were stuck as zeroes. When you tried to write a 1 to the bad bits, the drive would report successfully, but reading the bits back would show a zero.

That isn't a problem with SSD technology, it is a problem with the drive firmware. All SSD's have some built-in ECC (as do hard drives), so the problem you see is just really really bad quality standards (Yay JMicron, Yay OCZ). If a Hard Drive had stuck bits, and didn't re-map the bad blocks and find it with the ECC, the same thing would happen.

SSD's simply don't have the same type of likelihood of catastrophic total failure that HD's have, and when they run out of write cycles, all the data doesn't dissapear. Other data integrity issues are quality issues and firmware issues that have little to do with SSD technology and everything to do with a bad product.

There are enough reports out there to be very wary of many of the cheap or old SSD drives -- their quality is bad.

On the other hand, there are some high quality ones that behave correctly in failure. The next generation of drives will be much better than the last across the board -- quality, performance, price, capacity -- and that next generation began shipping this quarter from some manufacturers, others are on the way.

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That isn't a problem with SSD technology, it is a problem with the drive firmware. All SSD's have some built-in ECC (as do hard drives), so the problem you see is just really really bad quality standards (Yay JMicron, Yay OCZ).

I know, that JMicron controller is real crap. But my point was that while the expected action, it isn't always guaranteed. So one should be wary of stating it as a universal benefit of SSD.

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