07-13-2007
How to reduce IOWAIT in linux
Hi All,
Any ideas how to reduce IOWAIT and increase disk speed on Linux server.
Server has 4 CPUs and with 8GB RAM.
Thanks in advance,
Regards,
Bache
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
i have a server constantly have high iowait, but i am not able to tell which process generate the most of io. none commands, such as iostat, sar, top will give me this kind of information.
hope there is some command can help me to spot the process generate the most of io
let to know input... (1 Reply)
Discussion started by: giantpanda77
1 Replies
2. AIX
hello, we have a aix 5.2 server with 8GB of ram. is it possible, without actually removing the hardware, to have the O/S think it has only 4GB of ram? We would like to see how the handles and responds if it only had 4Gb instead of the 8GB. Any ideas or suggestions? Thanks
Looks like i found... (6 Replies)
Discussion started by: zuessh
6 Replies
3. Shell Programming and Scripting
Hi ,
how can i reduce the or conditions:
if ]; then
whatever
fi (8 Replies)
Discussion started by: hitmansilentass
8 Replies
4. Linux
Hi all,
Under top command you could see some iowait output.
Is any way to locate which process(s) is causing the high percentage of iowait?
17:48:39 up 19 days, 18:54, 3 users, load average: 3.24, 3.14, 3.17
392 processes: 389 sleeping, 1 running, 2 zombie, 0 stopped
CPU states: cpu user... (3 Replies)
Discussion started by: will_mike
3 Replies
5. Shell Programming and Scripting
printf "\nClosing stats:\n" >> data.txt
echo >> data.txt
sed 's/^ \t*//;/^#/d;/^$/d' $stats | while read line
do
close=$(grep -w "^$line" $datafile | sed -e 's/\(.*\),\(.*\),\(.*\)/\2/')
if ; then
printf "%5d. %-s was not found in file\n"... (3 Replies)
Discussion started by: jafa401
3 Replies
6. Shell Programming and Scripting
Hi All,
Could some one help me to reduce the code...
if
then
./plist -m "$queuename" |grep $2|awk '{print $3}' >unlock.log
elif
then
./plist -m "$queuename" |grep $2|awk '{print $4}' >unlock.log
else
./plist -m "$queuename" |grep $2|awk '{print $5}' >unlock.log
.
.
.
.
... (1 Reply)
Discussion started by: harshakusam
1 Replies
7. SuSE
Hello,
I do not know Linux. It is a black box.
We have 2 virtuals servers (SAPVM01 and SAPVM06) in one physical server.
The first virtual system (SAPVM01) has a total size of 420 Gb and a free space of 170 GB. A SAP system is running.
The second virtual system (SAPVM06) has a total... (3 Replies)
Discussion started by: daniel04
3 Replies
8. UNIX for Dummies Questions & Answers
Hi all
Can anyone advise/confirm whether total CPU usage when running sar is %user+%system+%iowait or is it %user+%system only?
I want to confirm whether I am having a CPU-bound problem or not.
This is a single-CPU VMware machine.
$ sar 5 20
Linux 2.6.18-238.5.1.el5... (7 Replies)
Discussion started by: newbie_01
7 Replies
9. Shell Programming and Scripting
Hello, I need to monitor IOwait on a server and have started this script directly on the ssh prompt.
Effectively it almost does what it is supposed to do, but I have no idea how to stop it?
How can I make it run it as a file based bash script?
(
iostat -xk 1 /dev/sdb2 | \
perl... (10 Replies)
Discussion started by: cuantica
10 Replies
10. Red Hat
Hello guys,
I would like to ask you kindly if you don't know some quick and safe method how to shrink ext4 filesystem and reduce the size of a Logical Volume in Linux, please?
Thank you very much. (2 Replies)
Discussion started by: los_bandidos
2 Replies
RAM(4) Kernel Interfaces Manual RAM(4)
NAME
ram - ram disk driver
SYNOPSIS
/sys/conf/SYSTEM:
NRAM ram_size # RAM disk size (512-byte blocks)
major device number(s):
block: 3
minor device encoding:
must be zero (0)
DESCRIPTION
The ram pseudo-device provides a very fast extended memory store. It's use is intended for file systems like /tmp and applications which
need to access a reasonably large amount of data quickly.
The amount of memory dedicated to the ram device is controlled by the NRAM definition in units of 512-byte blocks. This is also patchable
in the system binary through the variable ram_size (though a patched system would have to be rebooted before any change took effect; see
adb(1)). This makes it easy to test the effects of different ram disk sizes on system performance. It's important to note that any space
given to the ram device is permanently allocated at system boot time. Dedicating too much memory can adversely affect system performance
by forcing the system to swap heavily as in a memory poor environment.
The block file accesses the ram disk via the system's buffering mechanism through a buffer sharing arrangement with the buffer cache. It
may be read and written without regard to physical disk records. There is no `raw' interface since no speed advantage is gained by such an
interface with the ram disk.
DISK SUPPORT
The ram driver does not support pseudo-disks (partitions). The special files refer to the entire `drive' as a single sequentially
addressed file.
A typical use for the ram disk would be to mount /tmp on it. Note that if this arrangement is recorded in /etc/fstab then /etc/rc will
have to be modified slightly to do a mkfs(8) on the ram disk before the standard file system checks are done.
FILES
/dev/ram block file
/dev/MAKEDEV script to create special files
/dev/MAKEDEV.local script to localize special files
SEE ALSO
hk(4), ra(4), rl(4), rk(4), rp(4), rx(4), si(4), xp(4) dtab(5), autoconfig(8)
DIAGNOSTICS
ram: no space. There is not enough memory to allocate the space needed by the ram disk. The ram disk is disabled. Any attempts to access
it will return an error.
ram: not allocated. No memory was allocated to the ram disk and an attempt was made to open it. Either not enough memory was available at
boot time or the kernel variable ram_size was set to zero.
BUGS
The ram driver is only available under 2.11BSD.
3rd Berkeley Distribution Januray 27, 1996 RAM(4)