asr.tech.notes

Here are some handy ‘dig’ commands to verify DNS records: Do a hostname lookup # dig www.google.com ; <<>> DiG 9.4.1 <<>> www.google.com ;; global options:  printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 76 ;; flags: qr rd ra; QUERY: 1, ANSWER: 7, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;www.google.com.                        IN      A ;; ANSWER SECTION: www.google.com.         84790   IN      CNAME   www.l.google.com. www.l.google.com.       259     IN      A       209.85.148.104 www.l.google.com.       259     IN  ...

Add new devices to the system. Use rescan-scsi-bus.sh to scan for new devices or restart the system to get the new devices Create LVM Physical Volumes with the new devices # pvcreate /dev/sdxx Add the devices to the respective VGs # vgextend vgname /dev/sdxx Migrate the data from the existing PV to the new PV # pvmove /dev/sdxx o Where /dev/sdxx is the existing PV that needs to be removed from the VG List the PVs to make sure the PV that needs to be removed has no data on it   # pvs –o+pv_used PV VG Fmt Attr PSize PFree Used /dev/sda2 rootvg lvm2 a- 39.51g 8.63g 30.88g /dev/sda log2vg   lvm2 a- 30.00g 8.00g 0 /dev/sde log2vg   lvm2 a- 30.00g 8.00g 22.00g /dev/sdf datavg   lvm2 a- 100.00g 5.00g 95.00g /dev/sdg log1vg   lvm2 a- 30.00g 8.00g 22.00g In the above example, the data was moved from /dev/sda to /dev/sde (they reside in the same VG) Remove the PV from the VG   # vgreduce vgname /dev/sdxx Remove LVM PV inf...

Shared Ethernet Adapters on VIO server can be configured in two different modes while accessing the external network. 1.  Simple mode 2. Trunk mode or 802.1Q mode In a Simple mode, the SEA is not aware of any VLAN information and bridges all the network packets to the external switch.  the external switch then determines the target and routes/discards it accordingly.  This is very useful when there is only one VLAN that needs to be serviced through the SEA to the LPARs using these VIO servers.  The configuration on the switch as well as the VIO (SEA) is simple and straight forward.  In a Trunk mode (802.1Q complaint), the SEA is aware of the VLANs and bridges only the packets that is part of the ‘Additional VLANs’ list.  The external switch then determines the target and routes/discards it accordingly.  This is very useful when there is a need to service multiple VLANs through the same SEA adapter.  This will provide the ability to create LPAR...