[SOLVED] What size for swap partition?

[two4two]

I only have a 13G HDD for my Ubuntu (8.10). I installed with the defaults from the partitioner. It only gave me 510MB for the swap partition. Could this affect my downloads? Also, is there some kind of cache or temp storage where downloads are temporarily kept while the download is proceeding? I see Firefox has some cache for the size to be specified, but I'm talking about when I do the downloads for updates for Ubuntu. This is FTP and not involving the firefox browser. I ask this because it seems that when I do these downloads it gets so far and then slows down to a crawl. The downloads must have a timer because once they slow down they fail. Also, by that time Firefox browser won't work either any more. I use a TrendNet TEW-424UB (using the RealTek driver). Anyone have any ideas?

[pytheas22]

The packages that you download via Ubuntu updates ultimately get stored at /var/cache/apt. It's possible that they're copied into memory first and stored there until all downloads complete, but I suspect that that's not the case; they're probably written directly to disk, or cached in memory to a certain point and then written to disk as needed. In other words, they should have nothing to do with swap. Firefox downloads I believe work the same way--they get stored directly on your desktop as the download happens, not cached temporarily anywhere else (Internet Explorer does it differently).

From the behavior you're describing, it sounds more like your network interface is just crashing. This sometimes happen with certain devices when they're placed under heavy load, as yours would be if you're downloading a large number of updates at high speed for a sustained period of time.

The next time the crash happens, please immediately open a terminal, run the following commands (in this order) and post the output here:

dmesg | tail
lshw -C Network
ifconfig
ping -c 5 google.com
ping -c 5 72.14.207.99
lspci -nn
lsusb

That will help to figure out what's really going on when the downloads stop.

[PointyWombat]

If you suspect memory shortage problems, monitor swap behaviour to see if the swap device is actually being used. If it's not, then your problems are elsewhere. Use the free command, paying attention to the swap used metric. This value is typically zero. As you add memory load, you may start to see swap begin to be used as you run out of physical memory.

user@box:~$ free -s 1
             total       used       free     shared    buffers     cached
Mem:       2062192    1094792     967400          0      62236     638120
-/+ buffers/cache:     394436    1667756
Swap:      6040400          0    6040400

For your specific case though, I suspect memory shortfall is not the problem and pytheas22 is most likely on the right track.

[kansasnoob]

It would help to know your full system specs.

Processor speed:

 cat /proc/cpuinfo

Mem info:

 cat /proc/meminfo

[sazan]

swap size must be minimum of the size of ur RAM ...

[two4two]

Pointy, I entered the command as I think you wrote it and instead of just one reort back it just kept doing it over and over again and I didn't know how to stop it except for closing the terminal window. I see what you wrote as "free -s 1" (that's 1 as in one). What did I do wrong?

[ChildOfMana]

I see what you wrote as "free -s 1" (that's 1 as in one). What did I do wrong?

It should be a lower case L, not a 1.

A mistake I make on a regular basis! If in doubt; copy and paste are your friends

[egalvan]

I entered the command as I think you wrote... instead of one reort it kept doing it over and over again and I didn't know how to stop it except for closing the terminal window.

pressing
<ctrl>-<alt>-c
while the memory info is showing will stop the process.

[egalvan]

swap size must be minimum of the size of ur RAM ...

If you have enough physical ram, no swap is needed.

Swap comes into play when ram is lacking, or for 'sleep' or 'hibernation'.

[Lazy-buntu]

I've heard a range from the size of your RAM to two times your amount of RAM.