Samsung 256GB SSD is World's Fastest

i4u submitted one of many holiday weekend slow news day stories which starts "Samsung Electronics announced today the world's fastest, 2.5", 256GB multi-level cell (MLC) based solid state drive (SSD) using a SATA II interface. Performance data of the new Samsung 256GB SSD features a sequential read speed of 200 megabytes per second (MB/s) and sequential write speed of 160MB/s. The Samsung MLC-based 2.5-inch 256GB SSD is about 2.4 times faster than a typical HDD. Furthermore, the new 256 GB SSD is only 9.5 millimeters (mm) thick, and measures 100.3x69.85 mm. Samsung is expected to begin mass producing the 2.5-inch, 256GB SSD by year end, with customer samples available in September. A 256GB capacity is getting large enough to replace hard-drives for good — now just the prices just need to come down further for large capacity SSDs."

Comments

MLC, not SLC.

[Anonymous Coward]

But it's a Multi-Level Cell based Flash drive, not a Single-Level Cell based Flash drive. The cells hold 4 states, not 2.

High capacity, yes, and apparently high speed as well. Excellent... but also lower reliability. SLC Flash is extremely durable these days, but MLC Flash is not, last I checked, even one tenth as long-lasting.

How much lower? Well... ...frankly, we don't really know yet. We won't really know, as such, until they start to die - which could well be 5-10 years, and if so, that's really not bad - and you might not see the same type of can't-write-blocks failure, but rather a more conventional can't-read-blocks failure. Which would be about as bad as a hard disk crash (and we might have to develop whole new data recovery techniques).

Maybe it might last years longer than a hard drive owing to fewer moving parts. Perhaps it will slowly die, but good write levelling will largely mitigate the issue and overall it'll come out better, or about the same. Or perhaps we're looking at a flaky brick with lower reliability than a Quantum Fireball.

Early adopters, start your engines, because someone's gotta find out.

For enterprise use, it might be wiser to stick to more conservative SLC flash. Past that, all bets are off.

But we're seeing the beginning, here. Hard drives are, slowly, on the way out. It'll be a long phase-out where they are much more cost-effective for a long time... but it is coming. And I, for one, welcome our new nanosecond-seek-time overlords.

Re:A 128GB SATA drive costs $3,000

[Anonymous Coward]

You are comparing to the wrong technology. SLC drives are extremely expensive, but this is a MLC drive. You should look at these items instead to extrapolate cost:

Super Talent MLC Solid State Disks on Newegg

The Samsung drive is much higher performance than these, but the fabrication costs should not be too far off. I'd guess $1500 for the 256 GB model when it comes out.

Re:Random write ops?

[TheRaven64]

Unless flash has changed a lot since I last looked at it, this isn't quite true. To write a 2KB page, you first need to erase a 128KB block, but you can then write into the remaining 126KB without needing an erase first. If you're using something like LFS or ZFS on your disk, this translates to very fast writes. If you're using a filesystem that doesn't have copy-on-write semantics, then this will still be quite slow because you will rarely encounter this kind of access pattern (you will be more likely to read 128KB, modify 2KB in a buffer and then re-write 128KB, which, as you explained, is very slow since it requires a 128KB read followed by a 128KB write just to write 2KB - the same reason that RAID-5 is slow for writes).

Re:Summary

[TheRaven64]

And since it's using MLCs, expect to buy another one quite soon after. While SLC flash is up to the 100,000 to 1,000,000 rewrites level, MLC is still closer to 10,000. This, combined with the larger cell sizes on most MLC products means that it is likely to wear out much faster. This is why most flash manufacturers are only pushing MLC technology for consumer electronics type applications (e.g. MP3 players), where you want high density and low cost but don't perform many writes.

Re:Random write ops?

[GreyWolf3000]

What you said doesn't contradict what I said at all. You can definitely achieve much better performance by not scattering your writes; sequential access is very fast. For random writes, you're going to have to seriously buffer to avoid wasting erase cycles. Fortunately, the same algorithm that avoids erase cycles for performance is also the same algorithm that does wear leveling. I don't know too much about ZFS or how copy-on-write would help except on a purely abstract level.