Hello, I use a P4 based machine running SuSE Linux 8.0. I have a 20 GB Hard Disk & 256 MB RDRAM. At the time of installation, I reserved around 500 MB space for the /swap directory. As intended, it should share memory with the Linux Swap space. The problem is that, when I issue the top command, it shows that used swap space is zero & my Physical Memory is 70% used. I think it's pretty high since I don't use any software which is heavy on system requirments. I tried the swapon command but in vain. Even eding the /etc/fstab file didn't help. Is there any way to force swapping of memory ?? Please enlighten .... Thanx in advance ... Bhaskar Ghose [The Linuxer]
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Hi,
On Mon, 30 Dec 2002, The Linuxer wrote: [snip]
for the /swap directory. As intended, it should share memory with the Linux
First thing, <swap> partitions are not mounted, so you should not see any /swap if you run 'df -h'.
Swap space. The problem is that, when I issue the top command, it shows that used swap space is zero & my Physical Memory is 70% used. I think it's pretty high since I don't use any software which is heavy on system requirments. I tried the swapon command but in vain. Even eding the /etc/fstab file didn't help. Is there any way to force swapping of memory ??
You should not. Swap is not like actual memory, it is just bare unformatted partition on you harddisk, which is used by the kernel swapper to place 'pages' of memory that are not immediately required for execution. Since this involves disk i/o it is very slow compared to RAM. The Linux kernel will begin swapping when it finds that it is running out of RAM space, idle processes are also swapped. All this depends on the priority of the process as well. For more discussion, see here:
http://people.debian.org/~psg/ddg/node81.html
Please enlighten .... Thanx in advance ... Bhaskar Ghose [The Linuxer]
[snip]
Best regards,
Rajesh
Happy new year to all....
I have almost the same problem, Running MySQL-MAX-2.32 on RedHat 8.0 on a P-IV,1024MB RAM,80GB IDE. The mysql spawns about 10-14 processes at a time, I have a script running which gathers router logs and puts them into the mysql database (about 1.6GB last count) then there are about 10 scripts running which are continuous scripts which are always sorting the data and putting them into their respective tables ...
My mem usage is about 1000MB almost all the time and the swap (1024MB partition) is about 10MB used at the most I know the RAM is the most preferred place to keep all the data, but when does the SWAP actually get used ....
more in depth explanation from all the great masters will be appreciated
thanks
Ripunjay Bararia
-----Original Message----- From: linuxers-admin@mm.ilug-bom.org.in [mailto:linuxers-admin@mm.ilug-bom.org.in]On Behalf Of Rajesh Deo Sent: Monday, December 30, 2002 10:42 PM To: linuxers@mm.ilug-bom.org.in Subject: Re: [ILUG-BOM] [ILUG-BOM]Linux swap not working.
Hi,
On Mon, 30 Dec 2002, The Linuxer wrote: [snip]
http://people.debian.org/~psg/ddg/node81.html (more info on swap)
[snip]
Best regards,
Rajesh
On Tuesday 31 December 2002 02:23 pm, Ripunjay Bararia (ILUG-MUM) wrote:
- LUG meet on 12 Jan. 2003 @ VJTI
Happy new year to all....
I have almost the same problem,
more in depth explanation from all the great masters will be appreciated
What happens in some memory management algorithms is that even if the dirty buffers (bufferes which are modified in the RAM) are written to the HDD the RAM is not freed. So if a process again wants the same page (memory segment) then it need not be brought from the HDD to the RAM. So your RAM usage which is shown as 70% (assume) then not all that memory is actually used by the kernel at that time. How ever if you stop some memory hogging processes like httpd, mysqld, named, squid then the buffers will be forced to be written to the disk and the memory will definately be vacated. But if these processes are running (as it seems to be the case with you - server process usually never die) then there is no use of vacating the RAM. To just verify that swap space is working (dont you trust Linus) what you probably can do is that start approx 20 instances of mozilla (approx 15*20 = 300MB RAM) or a VMware session and ask it to use 80% of the existing RAm, then hope that the RAM is completely used up. Other thing to verify this concept is to remove some RAM say 128 MB and still the RAM usage should be around 90% so that will proove that the RAM utilization (70% of 256MB = 180 MB) wasnt actually required and the kernel could live with less RAM and give the same performance. I hope you understand this crappy little explaination.
thanks
Ripunjay Bararia
-----Original Message----- From: linuxers-admin@mm.ilug-bom.org.in [mailto:linuxers-admin@mm.ilug-bom.org.in]On Behalf Of Rajesh Deo Sent: Monday, December 30, 2002 10:42 PM To: linuxers@mm.ilug-bom.org.in Subject: Re: [ILUG-BOM] [ILUG-BOM]Linux swap not working.
Hi,
On Mon, 30 Dec 2002, The Linuxer wrote: [snip]
http://people.debian.org/~psg/ddg/node81.html (more info on swap)
[snip]
Best regards,
Rajesh
hi there,
On Monday 30 December 2002 15:14, you wrote:
Happy new year to all....
I have almost the same problem,
more in depth explanation from all the great masters will be appreciated
What happens in some memory management algorithms is that even if the dirty buffers (bufferes which are modified in the RAM) are written to the HDD the RAM is not freed. So if a process again wants the same page (memory
[snip]
To just verify that swap space is working (dont you trust Linus) what you probably can do is that start approx 20 instances of mozilla (approx 15*20 = 300MB RAM) or a VMware session and ask it to use 80% of the existing RAm,
20 processes of mozilla wont take up 20*15 MB of ram. How do i know ? well i tried it. its about 46 MB. I guess the majority of the space is taken up by the code, so its reusable.
Ripunjay Bararia
rahul
hi there,
On Monday 30 December 2002 20:38, you wrote:
- LUG meet on 12 Jan. 2003 @ VJTI
Hello, I use a P4 based machine running SuSE Linux 8.0. I have a 20 GB Hard Disk & 256 MB RDRAM. At the time of installation, I reserved around 500 MB space for the /swap directory. As intended, it should share memory with the Linux Swap space. The problem is that, when I issue the top command, it shows that used swap space is zero & my Physical Memory is 70% used. I think it's pretty high since I don't use any software which is heavy on system requirments.
As far as i know the kernel tries to load all the programs it needs to run into the RAM, from the HDD. Its the primary memory. Loading programs into the RAM is the logical thing to do. As people have told me, there is not use of RAM if its free and you are swapping from the disk :-)
Only when its full does it swap out !
I tried the swapon command but in vain. Even eding the
/etc/fstab file didn't help. Is there any way to force swapping of memory ?? Please enlighten .... Thanx in advance ... Bhaskar Ghose [The Linuxer]
-rahul
-
Amish Munshi -
Nikhil Joshi -
Rahul Saxena -
Rajesh Deo -
Ripunjay Bararia (ILUG-MUM) -
The Linuxer