[CentOS] browsers slowing Centos 7 installation to a crawl

Tue Aug 6 14:30:05 UTC 2019
Denniston, Todd A CIV USN NSWC CD CRANE ID (USA) <todd.denniston at navy.mil>

> -----Original Message-----
> From: Tony Mountifield <tony at softins.co.uk>
> Sent: Tuesday, August 06, 2019 5:44 AM
> To: centos at centos.org
> Subject: Re: [CentOS] browsers slowing Centos 7 installation to a crawl
> In article <alpine.DEB.2.20.1908051718240.19025 at mail.cs.ndsu.nodak.edu>,
> Michael Hennebry <hennebry at web.cs.ndsu.nodak.edu> wrote:
> >
> > I'll need to do some digging to discover whether my box needs DDR2 or
> > I doubt it's DDR4.
> Do:
> # dmidecode | less
> and look for the entries for the existing RAM you have. It will also tell
> you if you have any unpopulated RAM slots ("No module installed").

In the mean time you could enable zswap[1] to make the most out of the ram and swap you do have.
according to [2] either add 'zswap.enabled=1' to the boot line or 'echo 1 > /sys/module/zswap/parameters/enabled'

On an EL6 system with 512M of ram (yes that is correct, .5GB, actually ~.4GB because some is shared with the intel video) I use up-to-date EL6 firefox reasonably comfortably at home using zswap, setting max_pool_percent to 40.

I am trying to remember which kernel 7 is running (I tend to use the elrepo LT kernel on EL6) and if it has zswap or only zram. 

before switching to the LT kernel I used zram [3] on the machine as swap space (pretending to be 90% of ram) instead and it works very fast, but when it runs out (say on a site with lots of JPGs) and you hit real swap again performance tanks VERY badly.  EL7 may have zram setup to swap in such a way that you can 'sysctl start zram' and try it out.

Good luck.

[1] https://en.wikipedia.org/wiki/Zswap
[2] https://www.kernel.org/doc/html/latest/vm/zswap.html
[3] https://en.wikipedia.org/wiki/Zram

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