Yes, shared memory is often not considered, because it can be used by many process - or it is counted several times.
A special type of shared memory is the SysV IPC (inter process communication), listed with
E.g. for the "Shared Memory" the listed PIDs are for the "Creator" and the "Last attacher".
Even the normal fork/exec to create a new process produces shared memory.
Because initially they are identical, they are not actually copied but the new process reuses the memory. They are really copied when the new process modifies it. This is called COW (copy on write).
Last edited by MadeInGermany; 10-29-2018 at 05:48 AM..
Hi All,
I have a question, can you guys please help me by giving your valuable suggestons:
I am using AIX 5L, running oracle 7 version. I need to increase the oracle memory to 40 MB more. Currently Oracle occupies 260M. I wanted to know whether I can increase the memory without any problem.... (1 Reply)
Hi All,
I have a question, can you guys please help me by giving your valuable suggestons:
I am using AIX 5L, running oracle 7 version. I need to increase the oracle memory to 40 MB more. Currently Oracle occupies 260M. I wanted to know whether I can increase the memory without any problem.... (3 Replies)
Hi,
We have AIX 5.1 machine of RAM 8 GB and paging space is 8GB. we are getting high memory usage of almost 99%.Can anybody please help in this ?
Partial vmstat o/p
kthr memory
----- -----------
r b avm fre
2 1 278727 1143
There is no paging issue.Becoz in... (5 Replies)
Hi Guys,
I wonder what would be the best way to determine how much memory is in use on any given time by the database processes. I thought about using ipcs -m command but I wonder if there any better way to determine this. Thanks.
Harby. (2 Replies)
Hi,
I have AIX 5.3TL8 two node cluster using HACMP and have 10g database using RAW devices. I am seeing gradual increase in comp% memory everyday and it reaches 100% and evicts the node, we had 4 evictions in 40days.
I am pasting vmstat and vmo output, anyone seen this issue?
... (5 Replies)
Hi All,
Anyone has script to monitor AIX total processes memory and cpu usage that contribute to the total memory and CPU utilize so far ?
The purpose of this is to analyze process memory trend.
Thanks.
Best Regards,
ckwan (2 Replies)
Hi All,
I have some questions regarding the performance, MEMORY/ Virtual Memory (paging /swap space)
Please see the nmon-MEMORY stats from my AIX LPAR.
24 GB --> RAM
3456 MB --> Paging Space
│ Memory ───────────────────────────────────────────────────────────────────────
│... (8 Replies)
Discussion started by: System Admin 77
8 Replies
LEARN ABOUT HPUX
shmem
shmem(5) File Formats Manual shmem(5)NAME
shmem - enable or disable System V shared memory
DESCRIPTION
The tunable is obsolete. The System V IPC shared memory subsystem is always enabled.
Shared memory is an efficient InterProcess Communications (IPC) mechanism. One process creates a shared memory segment and attaches it to
its address space. Any processes looking to communicate with this process through the shared memory segment, then attach the shared memory
segment to their corresponding address spaces as well. Once attached, a process can read from or write to the segment depending on the
permissions specified while attaching it.
WARNINGS
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun-
able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was
factory installed on your system, see at
AUTHOR
was developed by HP.
SEE ALSO shmmax(5), shmmni(5), shmseg(5).
Tunable Kernel Parameters shmem(5)