12-29-2003
"virtual mem=2x real memory"
i often heard this opinion, and also used it for some years. but this rule is very old i think and based on mashines with less memory. i'm working as an sunse and my "work" is often based on 16 to 32 GB RAM (or sometimes more) mashines, so you have to explain your costumers why should he have a swap base with 2x real memory..... you cannot spend 2 disks only for memory; there is 32 GB memory waiting for some work....
my way:
i use the same size of memory for swap, otherwise you won't survive a memory dump, and 1 GB for swap paging. i haven't got any problems since this new calculation.
greetings Preßy
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LEARN ABOUT DEBIAN
sys::statistics::linux::memstats
Sys::Statistics::Linux::MemStats(3pm) User Contributed Perl Documentation Sys::Statistics::Linux::MemStats(3pm)
NAME
Sys::Statistics::Linux::MemStats - Collect linux memory information.
SYNOPSIS
use Sys::Statistics::Linux::MemStats;
my $lxs = Sys::Statistics::Linux::MemStats->new;
my $stat = $lxs->get;
DESCRIPTION
Sys::Statistics::Linux::MemStats gathers memory statistics from the virtual /proc filesystem (procfs).
For more information read the documentation of the front-end module Sys::Statistics::Linux.
MEMORY INFORMATIONS
Generated by /proc/meminfo.
memused - Total size of used memory in kilobytes.
memfree - Total size of free memory in kilobytes.
memusedper - Total size of used memory in percent.
memtotal - Total size of memory in kilobytes.
buffers - Total size of buffers used from memory in kilobytes.
cached - Total size of cached memory in kilobytes.
realfree - Total size of memory is real free (memfree + buffers + cached).
realfreeper - Total size of memory is real free in percent of total memory.
swapused - Total size of swap space is used is kilobytes.
swapfree - Total size of swap space is free in kilobytes.
swapusedper - Total size of swap space is used in percent.
swaptotal - Total size of swap space in kilobytes.
swapcached - Memory that once was swapped out, is swapped back in but still also is in the swapfile.
active - Memory that has been used more recently and usually not reclaimed unless absolutely necessary.
inactive - Memory which has been less recently used and is more eligible to be reclaimed for other purposes.
On earlier kernels (2.4) Inact_dirty + Inact_laundry + Inact_clean.
The following statistics are only available by kernels from 2.6.
slab - Total size of memory in kilobytes that used by kernel for data structure allocations.
dirty - Total size of memory pages in kilobytes that waits to be written back to disk.
mapped - Total size of memory in kilbytes that is mapped by devices or libraries with mmap.
writeback - Total size of memory that was written back to disk.
committed_as - The amount of memory presently allocated on the system.
The following statistic is only available by kernels from 2.6.9.
commitlimit - Total amount of memory currently available to be allocated on the system.
METHODS
new()
Call "new()" to create a new object.
my $lxs = Sys::Statistics::Linux::MemStats->new;
It's possible to set the path to the proc filesystem.
Sys::Statistics::Linux::MemStats->new(
files => {
# This is the default
path => '/proc',
meminfo => 'meminfo',
}
);
get()
Call "get()" to get the statistics. "get()" returns the statistics as a hash reference.
my $stat = $lxs->get;
EXPORTS
No exports.
SEE ALSO
proc(5)
REPORTING BUGS
Please report all bugs to <jschulz.cpan(at)bloonix.de>.
AUTHOR
Jonny Schulz <jschulz.cpan(at)bloonix.de>.
COPYRIGHT
Copyright (c) 2006, 2007 by Jonny Schulz. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
perl v5.14.2 2012-03-09 Sys::Statistics::Linux::MemStats(3pm)