Re: [gentoo-user] swap on ssd?

[Florian Philipp <lists@binarywings.net>]

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Am 25.11.2012 23:46, schrieb William Kenworthy:
> Has anyone tried swap on ssd?  - has it killed the drive prematurely? -
> any other effects?
> 
> I have a system that is maxed with with 4G ram and tends to use swap
> heavily at times which slows things down ... so I am thinking a small
> ssd might help here.
> 

You should tell us which model you want to use. In any case, if it is
relatively recent, I don't think you can actually break it with write
cycles anymore unless you keep it 100% busy 24/7.

> Another slower alternative is a usb thumbdrive ... might try that later
> today as I have some around ... again anyone tried this and found
> something unexpected?
> 

Thumbdrives have much simpler wear leveling. They also use triple level
cells (TLC) which are even worse than the MLCs found in cheaper SSDs.
Not to forget that USB doesn't support proper DMA and therefore
increases CPU load. Long story short: Swapping on thumbdrives is as fast
as a snail riding a turtle -- but turtles have a longer life span.

Another idea:
You can try to reduce the swap load by using frontswap with zcache. It
compresses memory pages in RAM which would otherwise be swapped. You
still need swap but less often.

Enable
FRONTSWAP
CRYPTO
CONFIG_STAGING
CONFIG_ZCACHE

then add "zcache" to your boot parameters.

Regards,
Florian Philipp


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