Keith C. Perry on 15 May 2016 21:31:04 -0700

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Re: [PLUG] Using ZRAM for swap

It is, accept that the reserved memory space is compressed by around 2:1 so on a decent CPU (I don't think I would include the PIII in that category) you do better with zram than with a swap file or disk since the disk subsystem is going to be much slower than main RAM.

I gave it another go and bumping the zram up to 128M for swap and dropping the swapiness down to 40 did at least allow me to get a a page loaded.  Still takes awhile but zram out the box only allocate 25% of your RAM so bringing that to 100% (i.e. zram set to 128M) did make a difference even though the system still is unusable practically.

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Keith C. Perry, MS E.E.
Owner, DAO Technologies LLC
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(M) +1.215.432.5167

From: "John Kreno" <>
To: "Philadelphia Linux User's Group Discussion List" <>
Sent: Sunday, May 15, 2016 5:51:13 PM
Subject: Re: [PLUG] Using ZRAM for swap

zram sounds like ramdisk, I'm not sure that would work on a ram starved system. It'll likely just make your problem worse.

On Sun, May 15, 2016 at 5:46 PM, Rich Freeman <> wrote:
On Sun, May 15, 2016 at 1:40 PM, Keith C. Perry
<> wrote:
> 2) Has anyone use zram for swap?  If so, how is the experience compared to
> using dedicated swap partitions or swap files.

I have not used it for swap but was using it for a good year or so as
a tmpfs for volatile storage.  I was running recent stable kernels
over that period of time and did not notice any kind of instability
attributable to zram.  I imagine it would be fine for swap - that is
really its main use case.  I'd think that the obvious trade-off is
disk vs CPU, which is a pretty good trade-off for most systems.

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John Kreno

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