Linux: Difference between revisions
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*[[Distributions|Distributions]] | *[[Distributions|Distributions]] | ||
*https://kb.novaordis.com/index.php/Events_OS_Metrics | *https://kb.novaordis.com/index.php/Events_OS_Metrics | ||
*Linux on ircnet: #linux2 | |||
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*[http://www.slashroot.in/linux-system-io-monitoring http://www.slashroot.in/linux-system-io-monitoring] | *[http://www.slashroot.in/linux-system-io-monitoring http://www.slashroot.in/linux-system-io-monitoring] | ||
=== show what is doing most disk accesses === | ===show what is doing most disk accesses=== | ||
iotop | *iotop | ||
glances | [https://github.com/nicolargo/glances glances] | ||
=== IO statistics === | === IO statistics === | ||
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== FAQ == | == FAQ == | ||
=== check if virtual | === check if interface exists === | ||
/sys/class/net/$IF | |||
===check if virtual or physical machine=== | |||
dmidecode -s system-manufacturer | dmidecode -s system-manufacturer | ||
virt-who | virt-who | ||
lscpu | |||
virt-what | |||
===Find bios version=== | |||
dmidecode -s bios-version | |||
=== watch which files a process opens === | === watch which files a process opens === | ||
watch ls -l /proc/`pidof clamd`/fd | watch ls -l /proc/`pidof clamd`/fd | ||
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*lsusb | *lsusb | ||
*hwinfo | *hwinfo | ||
*lspci | *lspci | ||
*lscpu | |||
dmidecode -t baseboard | dmidecode -t baseboard | ||
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kpartx /dev/sdg | kpartx /dev/sdg | ||
partx -uv /dev/sdg (this one worked on centos 7.3!) | partx -uv /dev/sdg (this one worked on centos 7.3!) | ||
This one gave new disk size! | |||
echo 1 > /sys/block/sde/device/rescan | echo 1 > /sys/block/sde/device/rescan | ||
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echo "- - -" > /sys/class/scsi_host/host2/scan | echo "- - -" > /sys/class/scsi_host/host2/scan | ||
or scan all: | |||
echo "- - -" | tee /sys/class/scsi_host/host*/scan | |||
The winner so far: | The winner so far: | ||
blockdev --rereadpt /dev/sdg | blockdev --rereadpt /dev/sdg | ||
but may throw blockdev: ioctl error on BLKRRPART: Device or resource busy | |||
maybe | maybe | ||
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=== Create swapfile === | === Create swapfile === | ||
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Temporary: | Temporary: | ||
swapon -v /var/swapfile | swapon -v /var/swapfile | ||
In fstab: | In fstab: /var/swapfile swap swap sw,prio=-1 | ||
/var/swapfile swap swap sw,prio=-1 | |||
swapon failed: Invalid argument | swapon failed: Invalid argument | ||
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try kpartx instead | try kpartx instead | ||
===Find maximum depth of directory=== | |||
find /var/www -type d | awk -F"/" 'NF > max {max = NF} END {print max}' | |||
[[Category:System Administration]] [[Category:Linux]] | [[Category:System Administration]] [[Category:Linux]] | ||
Revision as of 13:17, 11 July 2022
Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world. Developed under the GNU General Public License , the source code for Linux is freely available to everyone.
Links
- linux kernel
- Distributions
- https://kb.novaordis.com/index.php/Events_OS_Metrics
- Linux on ircnet: #linux2
Rescue CDs
Checking resources
*inxi *http://www.slashroot.in/linux-system-io-monitoring
show what is doing most disk accesses
*iotop glances
IO statistics
iostat vmstat dstat ioping atop
CPU usage etc
top atop htop vtop fio pidstat
Administration
FAQ
check if interface exists
/sys/class/net/$IF
check if virtual or physical machine
dmidecode -s system-manufacturer virt-who lscpu virt-what
Find bios version
dmidecode -s bios-version
watch which files a process opens
watch ls -l /proc/`pidof clamd`/fd
pam_succeed_if(sudo:auth): requirement "uid >= 1000" not met
Grow (GPT) last partition to max available
Where '3' is partition number
parted /dev/sdf resize 3 100%
No longer allowed?
gdisk
timestamp to human readable
date -d @1522142497
List hardware
- lshw
- dmidecode
- lsusb
- hwinfo
- lspci
- lscpu
dmidecode -t baseboard
BLKRRPART: Device or resource busy
spend all day or reboot
calling ioclt to re-read partition table: Device or resource busy
rescan partition table
Keep an eye on
cat /proc/partitions
Partition(s) have been written, but we have been unable to inform the kernel of the change
partprobe kpartx /dev/sdg partx -uv /dev/sdg (this one worked on centos 7.3!)
This one gave new disk size!
echo 1 > /sys/block/sde/device/rescan
Only one that seemed to work on (centos7.x)
echo "- - -" > /sys/class/scsi_host/host2/scan
or scan all:
echo "- - -" | tee /sys/class/scsi_host/host*/scan
The winner so far:
blockdev --rereadpt /dev/sdg
but may throw blockdev: ioctl error on BLKRRPART: Device or resource busy
maybe
hdparm -z /dev/sdg
Force reboot
I found sometimes 'reboot' and 'shutdown' don't work in virtual machines, in that case try:
#sync echo s > /proc/sysrq-trigger #optionally umount echo u > /proc/sysrq-trigger #reboot echo b > /proc/sysrq-trigger
Mignight commander/dialog strange characters
Quick fix:
export LANG=en_US.ISO-8859-1
This probleem seems to be related to screen/su -
kpartx failing silently
No output/result when trying to create:
kpartx -lv /dev/mapper/foo
this might means the device hasn't been partitioned
No output when trying to delete:
kpartx -d /dev/mapper/foop1
means you should use
kpartx -d /dev/mapper/foo
Create swapfile
fallocate -l 4G /var/swapfile mkswap /var/swapfile
Temporary:
swapon -v /var/swapfile
In fstab: /var/swapfile swap swap sw,prio=-1
swapon failed: Invalid argument
problably trying to use fallocate on rhel/centos, use dd instead
partx: error adding partition
try kpartx instead
Find maximum depth of directory
find /var/www -type d | awk -F"/" 'NF > max {max = NF} END {print max}'
