[SOLVED] using loads of ram--loading Slackware and maybe other stuff into RAM

dchmelik · 07-13-2015, 09:58 PM

My PC has 64 GB RAM because for 10+ years I have used a PC for distributed computing, like BOINC, GIMPs, and I have other projects I thought potentially could have used a lot (even opening large art files, or maybe one day, programming).

Someone on FreeNode IRC ##slackware suggested with the amount of RAM I have, I should load Slackware (and maybe other stuff) into RAM. How would I go about doing this?

drgibbon · 07-14-2015, 02:33 AM

One part of the filesystem you can safely mount in RAM is /tmp, by changing it in /etc/fstab

Code:

tmpfs            /tmp             tmpfs       defaults,nodev,nosuid         0   0

I think by default it allows for half of your RAM (but doesn't allocate it until something is actually put into /tmp). Some people talk about mounting /var into RAM as well, but this doesn't seem like a good idea since /var is expected to persist across reboots.

e5150 · 07-14-2015, 05:27 AM

Have a look at http://www.linuxquestions.org/questi...2/#post4482138 although it's almost been four years, I reckon it should still work roughly the same.

a4z · 07-14-2015, 06:25 AM

Quote:

Originally Posted by dchmelik

My PC has 64 GB RAM because for 10+ years I have used a PC for distributed computing, like BOINC, GIMPs, and I have other projects I thought potentially could have used a lot (even opening large art files, or maybe one day, programming).

Someone on FreeNode IRC ##slackware suggested with the amount of RAM I have, I should load Slackware (and maybe other stuff) into RAM. How would I go about doing this?

makes not that much sense, you need to read the distro and load it into ram,
there can you start the program directly also, might be faster

the view milliseconds you gain when starting binaries, ...
dlls are in the ram
hd has super fast chace
ssd is fast ..

and if you have persistent data you need to sync it anyway

no, makes onlly senes if you load from a slow medium like sdcars ...have spezial requirements...

drgibbon · 07-14-2015, 08:53 AM

I don't think it's a good idea to load the entire system into RAM if it's solely for a performance boost (check this post from TobiSGD). As he says, it makes more sense to run the system from a decent SSD and do disk intensive stuff in /tmp (mounted in RAM). If it's just for fun or to set up some kind of non-persistent system then I guess so.

orbea · 07-14-2015, 09:01 AM

Quote:

Originally Posted by drgibbon

One part of the filesystem you can safely mount in RAM is /tmp, by changing it in /etc/fstab

Code:

tmpfs            /tmp             tmpfs       defaults,nodev,nosuid         0   0

I think by default it allows for half of your RAM (but doesn't allocate it until something is actually put into /tmp). Some people talk about mounting /var into RAM as well, but this doesn't seem like a good idea since /var is expected to persist across reboots.

You can specify how much space tmpfs will use also, some programs like icecat will need to be compiled elsewhere for being fat though.

Code:

tmpfs		 /tmp		  tmpfs	      size=4G,nodev,nosuid	       0   0

Slax-Dude · 07-14-2015, 11:02 AM

Well, I experimented with zram a while ago...
I had a read-only "gold image" (in RAM) that was used in 6 or 7 VMs (windows server 2003)
They had a read-write snapshot where changes were recorded (on a HDD).
Needless to say that they went a lot faster

Unfortunately, zram is no longer present in Slackware64-14.1

Sefyir · 07-14-2015, 03:40 PM

I would actually suggest not rebooting as a method and just suspending when you're done with the computer.
Linux already uses all that ram since every program, every file is automatically loaded into ram after you open it initially.

Run this command to see information about your ram:

Code:

free -m

Here's my output

Code:

             total       used       free     shared    buffers     cached
Mem:         15720      13737       1983       3283        569      10304
-/+ buffers/cache:       2863      12857
Swap:            0          0          0

out of 16gb, 12.8gb of it is being used for buffer.

See here for more info http://www.linuxatemyram.com/

So while you can setup something that loads everything into ram at bootup, the kernel is already doing a lot of this automatically. If you work with a diverse amount of stuff and not rebooting (resetting the ram usage), you've probably already been making use of a lot of your total capacity.

This secondary page to linuxatemyram makes the point pretty well.

Code:

$ time python hello.py
Hello World! Love, Python

real	0m1.026s
user	0m0.020s
sys	0m0.020s

$ time java Hello
Hello World! Regards, Java

real	0m2.174s
user	0m0.100s
sys	0m0.056s

$ 

Wow. 1 second for Python, and 2 seconds for Java? That's a lot just to say hello. However, now all the file required to run them will be in the disk cache so they can be fetched straight from memory. Let's try again:

$ time python hello.py
Hello World! Love, Python

real    0m0.022s
user    0m0.016s
sys     0m0.008s

$ time java Hello
Hello World! Regards, Java

real    0m0.139s
user    0m0.060s
sys     0m0.028s

$ 

Yay! Python now runs in just 22 milliseconds, while java uses 139ms. That's 45 and 15 times faster! All your apps get this boost automatically!

dchmelik · 07-14-2015, 05:17 PM

I do not normally shut off, reboot, or suspend my computer, and will not start doing the last since I never seem to be able to come out of it. Ok, maybe I will not load Slackware to RAM, since I already have a SSD. The '/tmp' directory is something I wanted to not load to RAM, because if I build packages with SBo, forget, reboot, then they will all be gone.

drgibbon · 07-15-2015, 07:04 AM

Quote:

Originally Posted by dchmelik

The '/tmp' directory is something I wanted to not load to RAM, because if I build packages with SBo, forget, reboot, then they will all be gone.

You can have sbopkg build your source code in /tmp with the resulting packages stored elsewhere. For that you want to edit /etc/sbopkg/sbopkg.conf and change

Code:

export OUTPUT=${OUTPUT:-/tmp}

to somewhere outside of /tmp

bassmadrigal · 07-15-2015, 08:38 AM

Have a look at this thread for more information.

https://www.linuxquestions.org/quest...sk-4175527521/