session stalled when transfer files between two sites with unstable internet connection

net.core.rmem_default = 524288


net.core.rmem_max = 524288

net.core.wmem_default = 524288

net.core.wmem_max = 524288

net.ipv4.tcp_wmem = 4096 87380 524288

net.ipv4.tcp_rmem = 4096 87380 524288

net.ipv4.tcp_mem = 524288 524288 524288

net.ipv4.tcp_rfc1337 = 1

net.ipv4.ip_no_pmtu_disc = 0

net.ipv4.tcp_sack = 1

net.ipv4.tcp_fack = 1

net.ipv4.tcp_window_scaling = 1

net.ipv4.tcp_timestamps = 1

net.ipv4.tcp_ecn = 0

net.ipv4.route.flush = 1

ref: http://ubuntuforums.org/showthread.php?t=891695

wmi-client for linux

http://pzolee.blogs.balabit.com/2010/09/wmi-client-for-linux/

glibc version issue

in order not to upgrade the whole system to support some specific program, you can pull the required library from the compatible system to desired platform and have LD_PRELOAD or LD_LIBRARY_PATH defined before invoking the process.
in bash
LD_PRELOAD="......" glibc.so target_process

lmgrd去跑vendor daemon會有問題
此時僅需暫時修改預設loader,待lmgrd成功啟用後,在改回預設loader即可

nis map management

nested nfs automount issue
after revising the automap and then push the revised map to clients, nested mount will not appear.

Ans: need to force unmount the map root and restart nfs client
umount -l, fuser -k ....

asterisk cli kill call

show current channels --> core show channels
hangup a call --> channel request hangup |

rpm extraction

rpm2cpio myrpmfile.rpm | cpio -idmv

RHEL/CentOS softraid

1: create softraid volume
2: raid assignment
grub> device (hd0) /dev/sda

grub> device (hd1) /dev/sdb
grub> root (hd0,0)
grub> setup (hd0)
grub> root (hd1,0)
grub> setup (hd1)
grub> quit