Test the connectivity to server using netcat
Use netcat to test a connection by opening a socket on the server and connecting from a client on the network.
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389 notes on Linux, tools and troubleshooting
Diskdump report error messages when restart the diskdump service
After changing the diskdump configuration and restarting its service, errors may appear in /var/log/messages: diskdump: diskdumpctl: failed to add /dev/hdb! diskdump: a
Fix the following error; LVM error VG meta data inconsistent
Resolve LVM error VG meta data inconsistent by booting into rescue mode, restoring VG metadata, rescanning devices and groups, and activating the volume group.
Use IPv6 address be specified with scp, sftp and ssh
Use scp, sftp, and ssh with IPv6 addresses by enclosing the address in square brackets, as demonstrated with fe80::219:99ff:fe20:c251.
Suggested I/O scheduler for a Video on Demand (VOD) server using Red Hat Enterprise Linux
On a VOD server, using the cfg scheduler can increase disk I/O latency when many connections arrive, leading to uneven video playback.
Decrease the time for rebuilding the RAID 1 array
To reduce RAID 1 rebuild time, use: # mdadm -C /dev/md0 -l1 -n2 /dev/sda1 /dev/sda2 --bitmap=internal. --bitmap (Write-intent bitmap) reduces synchronization time…
Re-shape or Grow a Raid 5 array.
Growing Linux software RAID is straightforward. This example adds /dev/sdd1 to a three-disk RAID 5 array at /dev/md0, then grows the array and filesystem.
How to enable xdmcp
The XDMCP configuration file has moved from /etc/X11/gdm/gdm.conf to /etc/gdm/custom.conf. To enable XDMCP, edit the section under xdmcp.
Other Virtual network interfaces go down when bring down virtual network interfaces
With multiple virtual network interfaces, bringing one interface down may also bring down others. This example uses eth0:0, eth0:1, eth0:2, and eth0:3.