Preventative measures:
If you have not yet done so, limit ZFS ARC cache to RAM/4 in /etc/system:
Also watch /tmp; have a cleanup routine, and limit it to RAM/3 in /etc/vfstab:
--
Separate measurement of RAM and swap can be done for statistics - but rarely for alert thresholds.
Instead you should measure the virtual memory, as given by "vmstat" or "swap -s". It is roughly the sum of RAM and swap.
I need to put a program together to determine the total, available memory and total and available swap on unix machines. I have been searching for weeks and I seem to run into dead ends. Every unix platform I look at has a different way to determine memory info.
Any sugggestions or new... (4 Replies)
All,
The (fre) coloumn of the (vmstat) command, does it report the size of the free list including the swap space or it only report on the RAM (physical memory).
BR, (1 Reply)
Hi friends
i have a query.
we have two p-series machine(p550 & p570) with HACMP 5.3 and AIX 5.3 hosting SAP.
Now i need to now is there a way or a command to check the memory utilization on these machines on daily basis. I have tried vmstat and iostat but still it's not clear.
We have... (3 Replies)
Hello All,
I am trying to create a script that will give me the processes that consume swap in %.
i am using the below line to get it done.
virtual=`echo "$virtual/$swp*100"|bc -l|sed -e "s/\(\.\).*/\1/g"`
but getting the following output after running it.
.039
.110
I want the... (3 Replies)
Hi Experts,
Our servers running Solaris 10 with SAP Application. The memory utilization always >90%, but the process on SAP is too less even nothing.
Why memory utilization on solaris always looks high?
I have statement about memory on solaris, is this true:
Memory in solaris is used for... (4 Replies)
Hi,
I am new to AIX, Can someone please help me how to know the swap space, total physical memory and system cache?
We are using AIX 5.3.
Thanks! (3 Replies)
Hi,
i am new to linux/RHEL 6.0 and i have two questions.
1) How to get the CPU utilization and Memory Utilization of all Services running currently?
2) How to get the CPU utilization and Memory Utilization of all Applications running currently?
Please help me to find the script.
... (2 Replies)
Discussion started by: nossam
2 Replies
LEARN ABOUT FREEBSD
md
MD(4) BSD Kernel Interfaces Manual MD(4)NAME
md -- memory disk
SYNOPSIS
device md
DESCRIPTION
The md driver provides support for four kinds of memory backed virtual disks:
malloc Backing store is allocated using malloc(9). Only one malloc-bucket is used, which means that all md devices with malloc backing
must share the malloc-per-bucket-quota. The exact size of this quota varies, in particular with the amount of RAM in the system.
The exact value can be determined with vmstat(8).
preload A file loaded by loader(8) with type 'md_image' is used for backing store. For backwards compatibility the type 'mfs_root' is also
recognized. If the kernel is created with option MD_ROOT the first preloaded image found will become the root file system.
vnode A regular file is used as backing store. This allows for mounting ISO images without the tedious detour over actual physical media.
swap Backing store is allocated from buffer memory. Pages get pushed out to the swap when the system is under memory pressure, otherwise
they stay in the operating memory. Using swap backing is generally preferable over malloc backing.
For more information, please see mdconfig(8).
EXAMPLES
To create a kernel with a ramdisk or MD file system, your kernel config needs the following options:
options MD_ROOT # MD is a potential root device
options MD_ROOT_SIZE=8192 # 8MB ram disk
makeoptions MFS_IMAGE=/h/foo/ARM-MD
options ROOTDEVNAME="ufs:md0"
The image in /h/foo/ARM-MD will be loaded as the initial image each boot. To create the image to use, please follow the steps to create a
file-backed disk found in the mdconfig(8) man page. Other tools will also create these images, such as NanoBSD.
SEE ALSO disklabel(8), fdisk(8), loader(8), mdconfig(8), mdmfs(8), newfs(8), vmstat(8)HISTORY
The md driver first appeared in FreeBSD 4.0 as a cleaner replacement for the MFS functionality previously used in PicoBSD and in the FreeBSD
installation process.
The md driver did a hostile takeover of the vn(4) driver in FreeBSD 5.0.
AUTHORS
The md driver was written by Poul-Henning Kamp <phk@FreeBSD.org>.
BSD October 30, 2007 BSD