Monday, June 08, 2015

[dqrobvki] Alternatives to solid state swap

Using a solid state disk as swap, while not recommended because it is a medium with limited writes, does work surprisingly well compared to hard disk.

When a process starts swapping to hard disk a lot, the whole UI, the desktop environment, becomes so sluggish as to be unusable.  For a solid state disk as virtual memory, this does not happen; the latency is low enough not to affect UI (though it does noticeably affect the swapping process).

SSD is much cheaper then RAM.

Beyond wear, SSD also seems the wrong tool: it offers persistence through reboots, something not needed for virtual memory.  Persistence of memory may even be dangerous from a security or privacy standpoint.

We would like cheap, medium latency, non-persistent (volatile) memory.

Is the lowish latency of SSD an illusion caused by the embedded RAM on board the SSD package, which serves as a cache?

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