Hi Robin, We are mostly using Oracle 11.2.0.3 and 12.1.0.2. Some of our servers are in the AWS cloud and I can change OS parameters there. But for the servers that are running out of our server room, I need to justify any OS changes that I want. By default the servers allocate half the total memory to shared memory whether or not we are using AMM, or shared memory. Hence, I am trying to figure out what benefits we would get from shrinking /dev/shm on servers where we aren't using shared memory. Would it even make a difference.
---------- Post updated at 10:40 AM ---------- Previous update was at 10:11 AM ----------
For example, I increased the AMM memory on two databases on this server
from 1GB to 3GB, and the total memory allocated when down.
It just seems like Redhat is holding onto shared memory that would be better
off not being shred memory, thus reducing the amount of swap being used.
There are 12 databases on this server, most do not use shared memory.
I am running HP-UX B.11.11.
I'm increasing a parameter for a database engine so that it uses more memory to buffer the disk drive (to speed up performance). I have over 5GB of memory not being used.
But when I try to start the DB with the increased buffer parameter I get told.
"Not... (1 Reply)
I am using the ZLIB_VERSION "1.2.3" . The memory requirement for Zlib/GZIP compression is stated as
/* The memory requirements for deflate are (in bytes):
(1 << (windowBits+2)) + (1 << (memLevel+9))
that is: 128K for windowBits=15 + 128K for memLevel = 8 (default values)
... (0 Replies)
08-18-2008 11:00 AM
Cluster computing has played a pivotal role in the way research is conducted in educational environments. Because the amount of available money and hardware varies between university researchers, often it's necessary to find a clustering solution that can work well on a small... (0 Replies)
I've been referring bash info for processes and came across a structure for a process which is defined like
typedef struct process
{
struct process *next;
char ** argv
.
.
.
}process;
What I don't understand is that in the program there's a for loop which goes like this
job... (2 Replies)
Hi,
Im working on Solaris 9 on SPARC-32 bit running on an Ultra-80, and I have to find out the following:-
1. Total Physical Memory in the system(total RAM).
2. Available Physical Memory(i.e. RAM Usage)
3. Total (Logical) Memory in the system
4. Available (Logical) Memory.
I know... (4 Replies)
I'm running the following rsync command to sync a directory between the 2 servers:
rsync -az --delete --stats /some_dir/ server_name:/some_dir
I'm getting the following output:
Number of files: 655174
Number of files transferred: 14221
Total file size: 1138531979331 bytes
Total... (0 Replies)
Can someone explain the correlation between how sar names the disk drives and how the rest of the OS names the disk drives?
sar lists my disk drives as sd0, sd1, sd2, etc.....
while format lists my disk drives as c1t0d0, c1t1d0, c1t2d0,etc...
And also why sar shows 8 disks but format... (2 Replies)
Hello.
I am new to this forum and I would like to ask for advice about low level POSIX programming.
I have to implement a POSIX compliant C shared library.
A file will have some variables and the shared library will have some functions which need those variables.
There is one special... (5 Replies)
I stumbled upon this thread and one aspect of it got me thinking. As i am building a small Linux network right now for a friend i would like to hear your opinion on this.
I'd like to respectfully disagree. I think the Linux habit of disabling root login per default is wrong (not entirely... (6 Replies)
I am using xlC (Version: 11.01.0000.0011).
While build i am using "-g" to have debug information in build.
there are many object files (>500) due to which resultant shared file (.so) will have huge size.
I can't reduce optimization level.
Is there any way or flag is present by using which i... (2 Replies)
Discussion started by: Abhi04
2 Replies
LEARN ABOUT OSX
ipc::sharedmem
IPC::SharedMem(3pm) Perl Programmers Reference Guide IPC::SharedMem(3pm)NAME
IPC::SharedMem - SysV Shared Memory IPC object class
SYNOPSIS
use IPC::SysV qw(IPC_PRIVATE S_IRUSR S_IWUSR);
use IPC::SharedMem;
$shm = IPC::SharedMem->new(IPC_PRIVATE, 8, S_IRWXU);
$shm->write(pack("S", 4711), 2, 2);
$data = $shm->read(0, 2);
$ds = $shm->stat;
$shm->remove;
DESCRIPTION
A class providing an object based interface to SysV IPC shared memory.
METHODS
new ( KEY , SIZE , FLAGS )
Creates a new shared memory segment associated with "KEY". A new segment is created if
o "KEY" is equal to "IPC_PRIVATE"
o "KEY" does not already have a shared memory segment associated with it, and "FLAGS & IPC_CREAT" is true.
On creation of a new shared memory segment "FLAGS" is used to set the permissions. Be careful not to set any flags that the Sys V IPC
implementation does not allow: in some systems setting execute bits makes the operations fail.
id Returns the shared memory identifier.
read ( POS, SIZE )
Read "SIZE" bytes from the shared memory segment at "POS". Returns the string read, or "undef" if there was an error. The return value
becomes tainted. See shmread.
write ( STRING, POS, SIZE )
Write "SIZE" bytes to the shared memory segment at "POS". Returns true if successful, or false if there is an error. See shmwrite.
remove
Remove the shared memory segment from the system or mark it as removed as long as any processes are still attached to it.
is_removed
Returns true if the shared memory segment has been removed or marked for removal.
stat
Returns an object of type "IPC::SharedMem::stat" which is a sub-class of "Class::Struct". It provides the following fields. For a
description of these fields see you system documentation.
uid
gid
cuid
cgid
mode
segsz
lpid
cpid
nattach
atime
dtime
ctime
attach ( [FLAG] )
Permanently attach to the shared memory segment. When a "IPC::SharedMem" object is attached, it will use memread and memwrite instead
of shmread and shmwrite for accessing the shared memory segment. Returns true if successful, or false on error. See shmat.
detach
Detach from the shared memory segment that previously has been attached to. Returns true if successful, or false on error. See shmdt.
addr
Returns the address of the shared memory that has been attached to in a format suitable for use with "pack('P')". Returns "undef" if
the shared memory has not been attached.
SEE ALSO
IPC::SysV, Class::Struct
AUTHORS
Marcus Holland-Moritz <mhx@cpan.org>
COPYRIGHT
Version 2.x, Copyright (C) 2007-2010, Marcus Holland-Moritz.
Version 1.x, Copyright (c) 1997, Graham Barr.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
perl v5.16.2 2012-10-11 IPC::SharedMem(3pm)