Slashdot Mirror
Intel's First SSD Blows Doors Off Competition
theraindog writes "Intel is entering the storage market with an ambitious X25-M solid-state drive capable of 250MB/s sustained reads and 70MB/s writes. The drive is so fast that it employs Native Command Queuing (originally designed to hide mechanical hard drive latency) to compensate for latency the SSD encounters in host systems. But how fast is the drive in the real world? The Tech Report has an in-depth review comparing the X25-M's performance and power consumption with that of the fastest desktop, mobile, and solid-state drives on the market."
This article at HotHardware, has a few additional tests that show real-world usage models as well as synthetic benchmarks: http://www.hothardware.com/Articles/Intel-X25M-80GB-SATA-Solid-State-Drive-Intel-Ups-The-Ante/
The PCMark Vantage tests are especially impressive: http://www.hothardware.com/Articles/Intel-X25M-80GB-SATA-Solid-State-Drive-Intel-Ups-The-Ante/?page=7
That depends entirely on what kind of RAID we're talking about...
William of Ockham had no beard. The most likely explanation is that it was chewed off by squirrels every morning.
The reason you defrag a hard disk is because the time to read a file is much less if the drive doesn't have to a random-access seek while reading the file. SSDs have fast performance whether they need to seek randomly or not, so why would there be a need to defrag an SSD disk? I would think it would only wear out the drive faster.
What a fool believes, he sees, no wise man has the power to reason away.
Yeah, but the reason it speeds up mechanical hard drives is because your kernel can schedule I/O on multiple spindles, effectively parallelizing your I/O. Flash chips don't have to batch up a lot of transactions in memory and then block the process for long periods of time. Flash does not typically operate synchronous to the bus speed it's connected to, so you could get some speed benefits by accessing multiple banks in tandem, but probably not as much.
Slashdot: Where people pretend to be twice as smart as they really are by behaving like children.
Yes, it would wear the disk out faster, but your original premise is flawed.
Clustering locations would allow for accessing large chunks of data with one fetch, instead of lots of little fetches. If you're old enough, think back to the Blitter on the Amiga and moving contiguous chunks of memory as opposed fragmented blocks.
Remember, RAM can get fragmented just as badly as a hard drive.
Learning HOW to think is more important than learning WHAT to think.
You never want to defrag SSD's. It just wears out the disk.
A good SSD has wear-leveling and write-combining techniques that keep the SSD "defragmented" automatically.
And it doesn't matter if the FS clusters are far apart as long as they are close to the SSD's hardware cluster sizes or the SSD intelligently combines them (which is what I believe Intel is doing since they claim a write amplification of only 1.1).
It's possible that the Samsung SLC chip stores data for the wear-leveling and write-combining operations which would remap the MLC in a non-fragmented way.
BTW, let me give you a naive wear-leveling / write-combining algorithm. I'm sure Intel has a better one because they've invested millions of dollars of research and the one I'm about to present to you could be done by a CS101 student:
1) You have a bit more than 80GB free for an 80GB drive (extra memory to take care of bad sectors just like a normal hard drive plus a small amount of required for the wear-leveling / writecombining)
2) You treat most of the storage as a ring buffer that consists of blocks on two levels: the native block size and a subblock size. The remaining storage (or alternate storage which may be the Samsung SLC chip on the MLC drives) is used to journal your writes and wear-leveling.
3) You combine all writes aligned to the subblock size into a native block and write them out to the next free native block in the ring buffer and keep a counter for the write to the block. If you run into a used block, and increment a counter (for wear levelling) and if the counter is below a certain value, you skip it to the next free block, otherwise you move the used block (which has been stagnent) to a more frequently writtento free block (which will now take less of a burden since it's had a stagnant block moved into it).
4) Anytime you make a write, the new sectors are updated in the memory area used for journaling / wear-level / sector remapping.
Assuming your reads can be done fairly quickly at the subblock level, it never matters if you have to "seek" for the reads and the drive won't fragment on writes because they are combined into native block sizes.
Before rushing to buy these for database use, I would want a good look at MTBF values. Especially MTBF values for really heavy use, which may be completely different from estimated desktop use.