Swap = 2 x RAM

dtw · 2006-12-03 10:39:39

In these days of 1GB RAM as standard does it really make sense to have a 2GB swap partition?

My current box has 256 and my swap was comparable in size. I was getting poor performance in games so I upped it back to 512 and saw immediate improvements: less RAM usage and less swap space being used. So it seems there is some benefit of having that bigger swap, even if it never gets used.

What does everyone else think?

lessthanjake · 2006-12-03 10:47:47

I rather want my prosesses to die than to swap them, so I have no swap. My machine have 1GB ram, so if all ram is used up something is wrong and the one process using the most memory is probably the cause and it deserves to die anyway. I just let the kernel do the job for me. I have not noticed any performance hit and no swap also means longer battery life on my laptop.

lucke · 2006-12-03 10:53:19

Here (latest news entry) is what Con has to say about swap.

-edit-

Woo, not totally ontopic, but I've just found this and found it cool.

onearm · 2006-12-03 11:00:34

I have 1GB ram (soon 2GB) and only 256mb of swap (because I read somewhere that no swap wasn't good for the kernel, don't know if it's true or not). I have to say that the swap is never used unless when opening very big images in gimp, 2mb+.
I guess then that for ordinary desktop usage no or very little swap is ok

chrismortimore · 2006-12-03 12:17:47

I have 2G of ram on my desktop and 4G of swap, going by the swap = 2x ram. However, the swap partition lives on LVM2, so if I run out of space on the disc, I can always resize the swap. But given I have ~40G free just now on the system drive and ~60G free on my music & vids drive, I'm not exactly short of space just now...

Borosai · 2006-12-03 13:14:29

I decided to go with 512MB of swap (I have 4GB installed), and it will probably never be used, but whatever...I like saying "swap space."

[vEX] · 2006-12-03 14:26:42

I have 2GB RAM and a swap of 486MB and I've never seen the swap being used so far.

Romashka · 2006-12-03 14:39:55

I've never seen swap used on my server with 1GB RAM and Xfce on it, though I even run few vmware machines on it sometime.
I don't remember how much swap is there, probably 1GB.

arox1 · 2006-12-03 14:45:16

I have 450 MB RAM and I almost never use swap

20-30 MB was max when I was using heavy DE like KDE or gnome

slackhack · 2006-12-03 14:45:35

i have 1G ram and 1G swap, and like onearm says, i never see swap being used unless working with big image files. and even then it's pretty rare. on my server i see swap being used sometimes with a lot of torrents going, not sure why exactly. maybe it has something to do with network latencies and how it's writing to disk, since the target is an nfs partition.

vacant · 2006-12-03 16:51:04

Like most of you have found, swap space is redundant for your average desktop PC with a half-decent amount of RAM. Of course if you have some app going wildy out of control with a memory leak, then it just takes a bit longer to fill up any swap file before it grinds to a crawl. Gimp will use it's own temp files.

I've run happily with 512MB or more of RAM with no swap.

As a compromise, if you really can't be without swap space then use a swap file (rather than a swap partition) which you can reduce in size over the days down to zero - like letting the air out of your water wings until you can swim

dd if=/dev/zero of=/waterwings bs=1024 count=65536
chmod 600 /waterwings
mkswap /waterwings
swapon /waterwings

then to make it permanent when you next boot add this line to your /etc/fstab

/waterwings swap swap defaults 0 0

lucke · 2006-12-03 17:15:21

Having some decently sized swap partition has the other advantage of being able to use it for storing a suspend image (ha, I managed to create a one wicked sentence). But in that case using filewriter from suspend2 is also an option.

tardo · 2006-12-03 17:29:22

echo 1 > /proc/sys/vm/swappiness
for less swappiness. works like a charm for me. (2gb ram, 512mb swap)

Alphalutra1 · 2006-12-03 22:28:34

The 'b' partition of your first drive automatically becomes your system swap partition -- we recommend a minimum of 32MB but if you have disk to spare make it at least 64MB. If you have lots of disk space to spare, make this 256MB, or even 512MB. On the other hand, if you are using a flash device for disk, you probably want no swap partition at all. Many people follow an old rule of thumb that your swap partition should be twice the size of your main system RAM. This rule is nonsense. On a modern system, that's a LOT of swap, most people prefer that their systems never swap. Use what is appropriate for your needs.

This is what openbsd devels think of swap. I just use around 256 to 512 MB depending on the pc.

Cheers,

Alphalutra1

skottish · 2006-12-03 23:21:12

The only time my system goes into swap is when I do something incredibly stupid with my Gimp scripts. Unfortunately that's frequently. In fact, I botched a script earlier today that actually sent my system into swap when I still had 2 GBs of RAM still open. Now that's a memory leak!

brazzmonkey · 2006-12-08 14:40:41

under heavy load (multitasking + windows xp on vmware with many heavy excel files opened) my system does swap (a little).
as my rule of thumb i'd allocate at least 1xRAM as swap space. what about if swap is used for hibernation ?

Romashka · 2006-12-08 15:41:04

brazzmonkey wrote:

under heavy load (multitasking + windows xp on vmware with many heavy excel files opened) my system does swap (a little).

This depends on amount of RAM for host and guest system.
On my server with 1GB of RAM I run 3 vmware machines with 256 MB RAM - and no swapping (I have Xfce).

Also, VMware has 3 different policies on swapping virtual machine's memory.

iBertus · 2006-12-08 16:53:11

My current setup is 2GB RAM and 2GB swap. I've got plans to work with some really huge uncompressed datasets and 2GB of RAM may not be enough to get the job done. Unfortunately, my Soltek mainboard only has 2 sockets, so unless I want to build a new box 2GB installed RAM is the limit.

dolby · 2006-12-08 16:54:29

from my experience 1gb swap space is ok , maybe even too much for any machine no matter the amount of ram.
currently i run arch on a 128 ram machine with 1gb swap and most ive seen used is 100mb
dont know if having eg. 4gb ram with 1gb swap and not 8gb one by the 2xram "rule" , would slow things down, but i seriously doubt it. if anyone has such experience id like to know though

fk · 2006-12-08 17:06:18

Normally I think 300Mb of swap are enough, but what is when I will Suspend to Disk the System? Do I need more Swap space? (If I use the swap partition for this)

btw: what is better Suspend to Disk with a swap partition, or with a File?

Master Beef · 2006-12-12 21:49:49

i run my desktop with 1gb ram and a 2gb swap. the only time i've seen it used is video encoding. the size of the partition is irrelevent to me as i have 2 80gb ide drives used for arch x86 and 64 respectivly and a 320gb sata for my home dir

skymt · 2006-12-13 01:51:14

Ironically, the more RAM you have, the less swap you need. A much better guideline is to pick a number based on how much memory you think you'll need (frequently 2G on a modern KDE/Gnome desktop, 1-1.5 G on a lightweight box), add a bit (just in case), then subtract your current RAM.

byte · 2006-12-13 02:46:22

256 MB ram plus 128 MB swap and I've never run into problems with typical desktop usage (yes, that excludes stuff like video editing).

iBertus · 2006-12-13 04:20:17

Master Beef wrote:

i run my desktop with 1gb ram and a 2gb swap. the only time i've seen it used is video encoding. the size of the partition is irrelevent to me as i have 2 80gb ide drives used for arch x86 and 64 respectivly and a 320gb sata for my home dir

I think this makes a very good point about swap. Almost everybody has 20+ GB drives these days and having 2GB as swap isn't really affecting your usage that much.

As stated earlier in this thread, I also use 2GB of swap. It never gets used, but I often manipulate large datasets and I cannot have apps crashing due to lack of memory when an option like swap exists.

pauldonnelly · 2006-12-15 23:34:57

skymt wrote:

Ironically, the more RAM you have, the less swap you need. A much better guideline is to pick a number based on how much memory you think you'll need (frequently 2G on a modern KDE/Gnome desktop, 1-1.5 G on a lightweight box), add a bit (just in case), then subtract your current RAM.

!!

I don't know what kind of RAM the big DEs want, but I can't imagine what kind of lightweight box would want 1-1.5 GB. My fairly lightweight systems with 512 MB RAM hardly ever touch swap at all.

Arch Linux

#1 2006-12-03 10:39:39

Swap = 2 x RAM

#2 2006-12-03 10:47:47

Re: Swap = 2 x RAM

#3 2006-12-03 10:53:19

Re: Swap = 2 x RAM

#4 2006-12-03 11:00:34

Re: Swap = 2 x RAM

#5 2006-12-03 12:17:47

Re: Swap = 2 x RAM

#6 2006-12-03 13:14:29

Re: Swap = 2 x RAM

#7 2006-12-03 14:26:42

Re: Swap = 2 x RAM

#8 2006-12-03 14:39:55

Re: Swap = 2 x RAM

#9 2006-12-03 14:45:16

Re: Swap = 2 x RAM

#10 2006-12-03 14:45:35

Re: Swap = 2 x RAM

#11 2006-12-03 16:51:04

Re: Swap = 2 x RAM

#12 2006-12-03 17:15:21

Re: Swap = 2 x RAM

#13 2006-12-03 17:29:22

Re: Swap = 2 x RAM

#14 2006-12-03 22:28:34

Re: Swap = 2 x RAM

#15 2006-12-03 23:21:12

Re: Swap = 2 x RAM

#16 2006-12-08 14:40:41

Re: Swap = 2 x RAM

#17 2006-12-08 15:41:04

Re: Swap = 2 x RAM

#18 2006-12-08 16:53:11

Re: Swap = 2 x RAM

#19 2006-12-08 16:54:29

Re: Swap = 2 x RAM

#20 2006-12-08 17:06:18

Re: Swap = 2 x RAM

#21 2006-12-12 21:49:49

Re: Swap = 2 x RAM

#22 2006-12-13 01:51:14

Re: Swap = 2 x RAM

#23 2006-12-13 02:46:22

Re: Swap = 2 x RAM

#24 2006-12-13 04:20:17

Re: Swap = 2 x RAM

#25 2006-12-15 23:34:57

Re: Swap = 2 x RAM

Board footer