01-19-2019
Note that some systems actively try to use otherwise unused memory to speed up running processes. For example, if a process starts reading from a large file, the system might read the next few blocks (or megabytes) of that file into a system buffer so the data will be in memory without having to wait for the disk to rotate if that process reads the next block.
If other processes start up need the memory that was used for read-ahead buffers they can be reallocated to the next process without affecting how fast the new process can be loaded.
Different versions of BSD, Linux, and UNIX systems use different algorithms to try to make efficient use of memory. And, different releases of each of those systems may change the algorithms as the vendors think they have learned something from past experiences.
In other words, there can be lots of "free" memory may be used to hold data that may soon be useful to someone even though it can be re-allocated immediately if someone asks for it to be put to a specific use.
These 2 Users Gave Thanks to Don Cragun For This Post:
10 More Discussions You Might Find Interesting
1. Solaris
Hi All,
I am trying to find the physical memory usage by each process/users.
Can you please let me know how to get the memory usage?.
Thanks,
bsraj. (12 Replies)
Discussion started by: bsrajirs
12 Replies
2. UNIX for Dummies Questions & Answers
Hi Guys,
How can i check the RAM usage for a particular user on the Linux machine.
What command can be used.
Thanks in advance,
Swapna (1 Reply)
Discussion started by: Swapna173
1 Replies
3. Shell Programming and Scripting
Hi i just wanted to know what is the code to display amount of RAM and also the percentage used? I know i can possibly use the vmstat code but what part indicates the RAM? Any help would be much appreciated. Thanks (1 Reply)
Discussion started by: warlock129
1 Replies
4. Linux
Hi
one of our applications that runs on our Linux server leaks memory resulting in Ram that was used by the program not being released back to the operating system once a file has been processed. the result is over a very short period virtual all the memory has been used. an example currently
... (8 Replies)
Discussion started by: treds
8 Replies
5. Solaris
Hi RAM of my system is 24 GB however when i checked the processes pids and counted the memory usage by pmap i found out that the total memory usage is 36 GB
It s obvious that my system might be using some of virtual memory or swap space . How can i check which memory it is using and how ..
... (9 Replies)
Discussion started by: Paarth
9 Replies
6. Red Hat
Hi team
I have three physical servers running on Red Hat Enterprise Linux Server release 6.2 with the following memory conditions:
# cat /proc/meminfo | grep -i mem
MemTotal: 8062888 kB
MemFree: 184540 kB
Shmem: 516 kB
and the following swap conditions:
... (6 Replies)
Discussion started by: hedkandi
6 Replies
7. OS X (Apple)
Hey there! I'm a new user here who registered because I couldn't get these kind of questions answered in the place I directly com from. :o
I've found a discrepancy in total RAM used and I can't figure out why it is. My only guess is there are some RAM used by some stuff impossible to identify,... (2 Replies)
Discussion started by: dasx
2 Replies
8. UNIX for Dummies Questions & Answers
Hi,
I will be creating a process myself and I want to know the average CPU and RAM used by the process over the lifetime of the process. I see that there are various tools available(pidstat) for doing , I was wondering if it possible to do it in a single command while creation.
Thanks in... (3 Replies)
Discussion started by: koustubh
3 Replies
9. UNIX for Beginners Questions & Answers
grpdsku program allows user to check their group disk space in a server environment. The data in the dialog box queries a text file. Each text file is labeled with a current timestamp. Results output to a msgbox. Also, results output to a csv file. The csv file is sent to the user via email
... (13 Replies)
Discussion started by: dellanicholson
13 Replies
10. UNIX for Beginners Questions & Answers
Hello,
I have been running under ubuntu 14.04 trusty and 18.04 bionic.
What I wonder is about:
* how to stop all process in case hdd capacity is almost full and create space for system files
* if possible, to prevent filesystem to write anything into hdd when there is such a risk
* if... (4 Replies)
Discussion started by: baris35
4 Replies
PACKAGE(1) General Commands Manual PACKAGE(1)
NAME
package - register package user via mailagent
SYNOPSIS
package address system version patchlevel [ mailpatches | notifypatches ]
DESCRIPTION
This command is not intended to be run directly by a user, but may appear in any mail whose subject is set to Command. Such mail will be
processed by the mailagent(1), which will extract all lines beginning with @SH, which may specify this command. The mailagent first sets
environment variables that will be used by the command.
Package is used to notify the author of a package about its users. It is normally generated automatically by the MailAuthor.U unit when
the user runs Configure.
If the patchlevel specified is not the latest for that system and version, mail is immediately sent suggesting that they upgrade and
remindng them how to request the latest patches.
The final parameter, if included may be set to mailpatches to specify that the user would like to have future patches mailed to them, or
notifypatches to specify that a mail notification of future patches should be sent, rather than the entire patch.
The user's address and notification request are saved in the file users in the package's directory.
Package performs an approximate address match in order to avoid duplicate entries. Whenever this elimination occurs, a warning message is
issued in the logfile. Two addresses will be said equivalent if one of them has an added machine name or if they are really equal. There-
fore, the following addresses are equivalent:
ram@acri.fr
ram@main.acri.fr
whereas the following two are not equivalent, unfortunately:
ram@acri.acri.fr
ram@main.acri.fr
When a user is asking to be left alone, it is important to let him know if the request failed, because he will be annoyed when the next set
of patches is issued and he still gets them despite his previous request. Therefore, if no approximate match occurs, a warning message is
sent back, with a list of addresses that are close to his own e-mail address, but not equivalent. Fortunately, the following addresses are
considered close:
ram@acri.fr
ram@somewhere.com
raphael@main.acri.fr
manfredi@acri.acri.fr
because they either have the same login (important when someone changes company) or share the same domain or sub-domain part.
In order to edit the users file, the edusers script should be used. For one thing, it will let you edit the users file from whatever pack-
age you name in the command line, but it will also properly lock the file so that the execution of package will stall for the duration of
the manual edition (provided you have a strict locking policy defined in your ~/.mailagent configuration file).
FORWARDING
Package supports command forwarding as described in the mailhelp(1) page.
FILES
~/.mailagent configuration file for mailagent.
System/users list of users of that system.
This file consists of single line records, one for each registered user. Each record consists of three tab-separated
fields.
The first field indicates the level of updates requested by the user by a single letter as follows:
M Mail future patches directly to the user when they are issued.
N Notify the user of future patches.
U The users chose to let the author know that they have tried the program, but does not wish to know about future
updates.
L The user is no longer interested in the program and wants to be left alone.
The second field is their last notified patch level, or a dash (-) if it is not known.
The third field is the user's Email address.
Log/agentlog mailagent's log file
AUTHORS
Graham Stoney <greyham@research.canon.oz.au>
Raphael Manfredi <Raphael_Manfredi@pobox.com> (minor enhancements)
SEE ALSO
edusers(1), mailagent(1), metaconfig(1).
PACKAGE(1)