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I've often wondered about this stuff. MLC SSDs are good for 10000 writes per 250k (iirc?) block. When you think about using an SSD for virtual memory, even wi
by AlisdairO 16y ago
I've often wondered about this stuff. MLC SSDs are good for 10000 writes per 250k (iirc?) block. When you think about using an SSD for virtual memory, even with wear levelling, that's really not very much at all. Add in programs that do lots of small file writes to logs and so on, and I can imagine losing a lot of blocks fairly quickly - particularly because wear levelling will cause you to lose all of the blocks in a relatively small time space, as opposed to gradual failure.
I wonder if, as flash memory gets cheaper, we'll see SLC SSDs getting more popular.
- Klinky 16y agoMore likely we'll just continue to see the firmware get smarter. SandForce controllers compress a lot of redundant data and only make writes when absolutely necessary. http://www.anandtech.com/show/4159/ocz-vertex-3-pro-preview-the-first-sf2500-ssd/2 http://www.anandtech.com/show/4159/ocz-vertex-3-pro-preview-...
- deleted 16y ago[deleted]
- Symmetry 16y agoIts actually good for 10,000 erases per block, so depending on how your file system works you could erase a block, then write to some of it, then rite to another part of it, then write to it again filling it up. Write amplification does occur for this reason and because the drive has to keep track of what it has on itself, but its usually not more than a factor of 2.
- wmf 16y agoIn reality, every erase is followed by exactly one (amortized) program, so it doesn't matter which one you track.
- Symmetry 16y agoReally? That seems to inefficient though... I not a huge expert on commercial SSDs, but when I've written my own flash drivers for embedded sensors I would always make use of multiple writes per erase.