Re: Debian's recommendation for the size of the swap.
For now I probably don't need that much. But my plans include setting my system up as a server for two windows machines, that should increase the demands on virtual memory. Attached is a free run. (with X, Netscape (reported to need 64M available), xterm fvwm95, xconsole running. ---shaul [EMAIL PROTECTED] wrote: If anyone is taking a survery... My machine also has 64M or ram, and I am using 128M of swap space (I figured with a 5.4GB drive I'd max out the swap partition.) I am curious if that size of swap is realy needed: could you email the results of a free command ? Thank you. _ DO YOU YAHOO!? Get your free @yahoo.com address at http://mail.yahoo.com foofree Description: foofree
Partition size technicalities. Re: Debian's recommendation for the size of the swap.
Pierfrancesco Caci wrote: [...] I've a machine with 64 MB ram, 1 swap partition of about 32 MB (made like that when I only had 32 MB ram) 1 swap file of 127 MB (it doesn't take 128 MB, you must put something less). [...] If you really want to know why this is (probably not), partition sizes are actually specified in cylinders. It is possible to define partition boundaries that do not lie on cylinder boundaries, but this can be very dangerous and most partitioning software only lets you do this with the 'expert options' or something similar. Most disks have a geometry that is something like num cylinders x 255 heads x 16 sectors x 512 bytes per sector. So the size of one cylinder is going to be 255x16x512, which is 2,088,960 bytes. Thus all of your partition sizes are going to be multiples of that, and the closest multiple to 128MB is 127,426,560 bytes. While not as important with ext2fs Linux and FAT32/Win, it's a good idea to size your partitions to the closest cylinder that resides under the power of 2 mark (31MB, 63MB, 511MB, etc) for minimal cluster sizes and minimal disk space wastage. Even though newer filesystems like ext2fs and FAT32 typically use 4k inodes or clusters, if you have 8GB partitions then there's going to be an incredible amount of clusters or accounting information and this will lower performance so it's good to use multiple, smaller partitions anyways for this reason and all the other reasons for using seperate /var, /tmp, etc. partitions. Christopher
Re: Debian's recommendation for the size of the swap.
If anyone is taking a survery... My machine also has 64M or ram, and I am using 128M of swap space (I figured with a 5.4GB drive I'd max out the swap partition.) I am curious if that size of swap is realy needed: could you email the results of a free command ? Thank you.
Re: Debian's recommendation for the size of the swap.
On Wed, Oct 14, 1998 at 11:34:16PM +0300, shaul wrote: (1) Linux accept up to 128MB for a single swap partition (2) There is (was) a rule of thumb to have a swap size as twice as the RAM the machine has (3) Having more RAM reduces the needs for swap. ya konw, i'm a little confused. people say more RAM reduce the needs for swap while swap is recommended for double size of RAM ? yeah, newbia i am :-P [01:30:15 shaul]$ grep -A18 Your swap partition /cdrom/install.txt Your swap partition will be used to provide virtual memory for the system and should be between 16 and 128 megabytes in size, depending on how much disk space you have and how many large programs you want to run. The old rule of thumb is that swap should be twice as big as the amount of physical memory you have available. Once you get past the 32MB of RAM mark, you shouldn't make your swap partition more than 1.5 bigger than the amount of RAM. Linux will not use more than 128 megabytes of swap on a single swap partition, so there's no reason to make your swap partition larger than that. However, you can make multiple swap partitions by hand and edit /etc/fstab af- ter you've installed to get more than 128 megabytes of swap. A swap partition is strongly recommended, but you can do with- out one if you insist, and if your system has more than 16 megabytes of RAM. If you wish to do this, please select the Do Without a Swap Partition item from the menu. [01:30:27 shaul]$ Does all this make sense ? Perhaps Debian should make a small survey among its users about the size of the swap size they are using ? i'm currently use 12M swap with 64M RAM, is it too few ? Well, IMHO it is too small. I wonder, could you send what free reports when your machine runs your usual apps? i feel ugly when open *guash*, and xemacs and netscape opened very slowly. i only have 2G hd, and 750M among it is spared for win98 'cause i need its support for chinese stuff. Will it get quicker if you'll create a swap file ? --zhaoway the exactly 9th registerd linux user in counter.li.org -- Unsubscribe? mail -s unsubscribe [EMAIL PROTECTED] /dev/null
Re: Debian's recommendation for the size of the swap.
On Wed, Oct 14, 1998 at 11:34:16PM +0300, shaul wrote: (1) Linux accept up to 128MB for a single swap partition (2) There is (was) a rule of thumb to have a swap size as twice as the RAM the machine has (3) Having more RAM reduces the needs for swap. ya konw, i'm a little confused. people say more RAM reduce the needs for swap while swap is recommended for double size of RAM ? yeah, newbia i am :-P Does all this make sense ? Perhaps Debian should make a small survey among its users about the size of the swap size they are using ? i'm currently use 12M swap with 64M RAM, is it too few ? i feel ugly when open *guash*, and xemacs and netscape opened very slowly. i only have 2G hd, and 750M among it is spared for win98 'cause i need its support for chinese stuff. --zhaoway the exactly 9th registerd linux user in counter.li.org
Re: Debian's recommendation for the size of the swap.
[EMAIL PROTECTED] wrote: On Wed, Oct 14, 1998 at 11:34:16PM +0300, shaul wrote: (1) Linux accept up to 128MB for a single swap partition (2) There is (was) a rule of thumb to have a swap size as twice as the RAM the machine has (3) Having more RAM reduces the needs for swap. ya konw, i'm a little confused. people say more RAM reduce the needs for swap while swap is recommended for double size of RAM ? yeah, newbia i am :-P That swap must be = 2*RAM is a common misconception in the Linux world. On BSD's this is a good rule of thumb, due to a different VM[1] subsystem design but on Linux only the RAM+swap figure matters. The only general rule for swap size is that you should have enough. That means that RAM+swap should be large enough to run the programs you are likely to run at any given time. Note, however, that you should always have *some* swap, even if all your programs will fit in RAM, to allow the kernel to swap out unused pages and make room for more buffers. Similarly, you should always have some unused VM to allow for extraordinary memory requirements and to make room for buffers. Did I mention that buffers are a good thing? :-) It is, of course, better to have too much swap space than too little. Horrible things will happen if you run out of VM: processes will be randomly killed off, the system may crash, etc. i'm currently use 12M swap with 64M RAM, is it too few ? i feel ugly when open *guash*, and xemacs and netscape opened very slowly. i only have 2G hd, and 750M among it is spared for win98 'cause i need its support for chinese stuff. I would probably add some some swap space, but as I outlined above, this is a very individual thing. My box has 64MB RAM + 96MB swap and it seems quite happy with that configuration. However, I probably use more VM than most people... [1] VM = Virtual Memory -- /'`\ zzzZ | My PGP Public Key is available at: ( - - ) | http://home1.inet.tele.dk/renehl/ --oooO--(_)--Oooo-- Don't ya just hate it when there's not enough room to fin
Re: Debian's recommendation for the size of the swap.
In [EMAIL PROTECTED], on 10/14/98 at 11:34 PM, [EMAIL PROTECTED] (shaul) said: that iconifying most of these windows has little effect on the memory usage. Yes, minimizing a program does not magically make it use less memory. Your screen may repaint faster though, when there's less to repaint. Does all this make sense ? Perhaps Debian should make a small survey among its users about the size of the swap size they are using ? I have 32M ram and 64M of swap on the home machine. I have seen it use 1.8M of swap when both running X games and compiling a kernel. I believe this will increase when I start using netscape and staroffice. :-) Helge Hafting -- --- [EMAIL PROTECTED] ---
Re: Debian's recommendation for the size of the swap.
i'm currently use 12M swap with 64M RAM, is it too few ? Here's what you do: $ free total used free sharedbuffers cached Mem:127660 120980 6680 21636 44904 35608 -/+ buffers/cache: 40468 87192 Swap:25580240 25340 I have 128 MB of RAM. I'm using all of it but 6.6MB, but I only really need 40MB for my applications, the rest of the 128MB is caching files that I have used recently. The next time I read them, they will already in RAM and Linux won't access the disk, thus the process will be 10 times faster. I'm hardly using my swap, and almost never do. -- Peter Galbraith, research scientist [EMAIL PROTECTED] Maurice Lamontagne Institute, Department of Fisheries and Oceans Canada P.O. Box 1000, Mont-Joli Qc, G5H 3Z4 Canada. 418-775-0852 FAX: 775-0546 6623'rd GNU/Linux user at the Counter - http://counter.li.org/
RE: Debian's recommendation for the size of the swap.
Hey all, I have to admit to ignorance on this subject, never spent much time worrying about swap file and VM. Never much interested me. But, for reading this discussion I have a question. I have 12M of Ram and 12M of Swap (could afford more only have 250M). Now if I have a program that requires 20M of Ram to run, then With my specs it should run? I'm I right on this one? Rod. -- From: [EMAIL PROTECTED]:[EMAIL PROTECTED] Sent: Thursday, October 15, 1998 1:51 AM To: debian-user@lists.debian.org Subject: Re: Debian's recommendation for the size of the swap. [EMAIL PROTECTED] wrote: On Wed, Oct 14, 1998 at 11:34:16PM +0300, shaul wrote: (1) Linux accept up to 128MB for a single swap partition (2) There is (was) a rule of thumb to have a swap size as twice as the RAM the machine has (3) Having more RAM reduces the needs for swap. ya konw, i'm a little confused. people say more RAM reduce the needs for swap while swap is recommended for double size of RAM ? yeah, newbia i am :-P That swap must be = 2*RAM is a common misconception in the Linux world. On BSD's this is a good rule of thumb, due to a different VM[1] subsystem design but on Linux only the RAM+swap figure matters. The only general rule for swap size is that you should have enough. That means that RAM+swap should be large enough to run the programs you are likely to run at any given time. Note, however, that you should always have *some* swap, even if all your programs will fit in RAM, to allow the kernel to swap out unused pages and make room for more buffers. Similarly, you should always have some unused VM to allow for extraordinary memory requirements and to make room for buffers. Did I mention that buffers are a good thing? :-) It is, of course, better to have too much swap space than too little. Horrible things will happen if you run out of VM: processes will be randomly killed off, the system may crash, etc. i'm currently use 12M swap with 64M RAM, is it too few ? i feel ugly when open *guash*, and xemacs and netscape opened very slowly. i only have 2G hd, and 750M among it is spared for win98 'cause i need its support for chinese stuff. I would probably add some some swap space, but as I outlined above, this is a very individual thing. My box has 64MB RAM + 96MB swap and it seems quite happy with that configuration. However, I probably use more VM than most people... [1] VM = Virtual Memory -- /'`\ zzzZ | My PGP Public Key is available at: ( - - ) | http://home1.inet.tele.dk/renehl/ --oooO--(_)--Oooo-- Don't ya just hate it when there's not enough room to fin
Re: Debian's recommendation for the size of the swap.
If anyone is taking a survery... My machine also has 64M or ram, and I am using 128M of swap space (I figured with a 5.4GB drive I'd max out the swap partition.) _ DO YOU YAHOO!? Get your free @yahoo.com address at http://mail.yahoo.com
Debian's recommendation for the size of the swap.
Debian's recommends (in its FAQ and the installation guide) to have about 50MB of swap file. I am using 50MB only as a representative number. I know it is also saying that (1) Linux accept up to 128MB for a single swap partition (2) There is (was) a rule of thumb to have a swap size as twice as the RAM the machine has (3) Having more RAM reduces the needs for swap. I think that this recommendation should be raise to the full 128MB that Linux accept for a single swap size, together with the saying that it can work with much less swap, that it is hard to determine a single number when almost each installation is different on its use and future needs, etc. My reasons are: 1) Application are getting bigger in their memory needs (netscape, xemacs, image proccessing, and more). And the rate that the applications are getting bigger seems to exceed the rate the memory chips are getting larger and cheaper. 2) Disk sizes are getting larger, so sparing as much as 128MB for swap size today is much less painfull and much more cheaper then sparing 50MB couple of years ago. 3) Resizing disks partitions when someone needs more swap is a problmatic process, and using swap files are not recommended. 4) Restaring an application seems to require more and more time. While saying all that, I am taking my machine a an example: [07:04:06 shaul]$ free total used free sharedbuffers cached Mem: 38344 37732612 17868208 8984 -/+ buffers/cache: 28540 9804 Swap:48380 43608 4772 [20:15:17 shaul]$ My machine is used as a desktop computer for a single user. It has only modem connection to the internet. Still, it uses a considerable amount of its memory resources. Then what am I doing with all that memory resources ? The answer is that I am using a 3x3 pages on my display, and tend to keep the programs open on one page while I am switching to another. I find it more comfortable to switch to a different display page then to use one page and open and close the programs that I want. Therefor, I am using simultansiouly a total of about 6 xterms (about one for each display page), one copy of netscape, one xemacs window, one DDD window, and 3 TkMan windows. A little experiment that I did show (?) that iconifying most of these windows has little effect on the memory usage. Does all this make sense ? Perhaps Debian should make a small survey among its users about the size of the swap size they are using ?
Re: Debian's recommendation for the size of the swap.
[EMAIL PROTECTED] (shaul) writes: 3) Resizing disks partitions when someone needs more swap is a problmatic process, and using swap files are not recommended. why do you say that swap files are not recommended ? I know the're slower than swap partitions, but I can't see what other problems can exist. Perhaps Debian should make a small survey among its users about the size of the swap size they are using ? I've a machine with 64 MB ram, 1 swap partition of about 32 MB (made like that when I only had 32 MB ram) 1 swap file of 127 MB (it doesn't take 128 MB, you must put something less). On another machine with only 16 MB ram I have a 127 MB partition and a 127 MB file. The file gets seldom used. Pf -- --- Pierfrancesco Caci | mailto:[EMAIL PROTECTED] - http://gusp.infogroup.it ik5pvx| http://www.geocities.com/SoHo/Lofts/8999 Firenze - Italia | Office for the Complication of Otherwise Simple Affairs Linux penny 2.1.122 #7 Thu Sep 17 13:56:01 CEST 1998 i586 unknown
