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Actually SSD themselves implement COW filesystem since NAND cannot be written without erase step.
by pkaye 11y ago
Actually SSD themselves implement COW filesystem since NAND cannot be written without erase step.
- pmalynin 11y agoWhat about TRIM?
- pkaye 11y agoTRIM is like the free() equivalent to malloc(). It releases a NAND page back to free state for other uses. It dones't require any NAND access or writes per-se but if persistent TRIM is needed (vs best effort,) it gets much more complicated.
- tominous 11y agoThat's true but not particularly relevant to database performance. As I mentioned, random reads on an SSD do not suffer from a head seek penalty so it doesn't matter how the blocks are allocated. On the other hand with spinning disk there is a huge difference in throughput for large sequential vs small random reads.