phoronix benchmarks ext4 vs. btrfs

[John Reiser]

> I think I'd rather see a portion of the SSD be a discrete device so that the system and application scratch/swap can be pointed to it - rather than as cache. I'm not sure that this data would always stay hot enough to be assured of being in an SSD cache, whereas a discretely defined device would.

If the usage pattern is well known, heavy, and bounded then a tmpfs may suffice.
If the usage pattern is even heavier and well-bounded, then a ramdisk may be good.
If usage is read-only or nearly so, then USB flash memory may be good, too.

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