Veritas Cluster Server (vcs) Interview Questions with Answers
Question: 1. What Are The Different Service Group Types?
Answer:
Service companies may be one of the 3 kind :
Failover – Service institution runs on one gadget at a time.
Parallel – Service organization runs on a couple of structures concurrently.
Hybrid – Used in replicated records clusters (disaster restoration setups). SG behaves as Failover in the local cluster and Parallel for the remote cluster.
Question 2. Where Is The Vcs Main Configuration File Located ?
Answer:
The essential.Cf record contains the configuration of the whole cluster and is positioned within the directory /and so on/VRTSvcs/conf/config.
Red Hat Linux System Administration Interview Questions
Question three. How To Set Vcs Configuration File (fundamental.Cf) Ro/rw ?
Answer:
To set the configuration record in read-handiest/examine-write :
# haconf -sell off -makero (Dumps in memory configuration to principal.Cf and makes it examine-most effective)
# haconf -makerw (Makes configuration writable)
Question four. Where Is The Vcs Engine Log File Located ?
Answer:
The VCS cluster engine logs is positioned at /var/VRTSvcs/log/engine_A.Log. We can either directly view this file or use command line to view it:
# hamsg engine_A
Unix/Linux Tutorial
Question 5. How To Check The Complete Status Of The Cluster?
Answer:
To test the status of the entire cluster :
# hastatus -sum
Solaris Interview Questions
Question 6. How To Verify The Syntax Of The Main.Cf File?
Answer:
To verify the syntax of the primary.Cf file simply point out the absolute directory course to the principle.Cf record :
# hacf -verify /etc/VRTSvcs/conf/config
Question: 7. What Are The Different Resource Types?
Answer:
Persistent : VCS can only screen those assets but can not offline or on line them.
On-Off : VCS can start and forestall On-Off aid kind. Most assets fall in this class.
On-Only : VCS begins On-Only sources but does not forestall them. An instance might be NFS daemon. VCS can start the NFS daemon if required, but can not take it offline if the related provider organization is take offline.
SSRS(SQL Server Reporting Services) Interview Questions
Question eight. Explain The Steps Involved In Offline Vcs Configuration?
Answer:
Save and near the configuration :
# haconf -sell off -makero
Stop VCS on all nodes within the cluster :
# hastop -all
Edit the configuration document after taking the backup and do the adjustments :
# cp -p /etc/VRTSvcs/conf/config/principal.Cf /and so on/VRTSvcs/conf/config/most important.Cf_17march
# vi /and so forth/VRTSvcs/conf/config/main.Cf
Verify the configuration record syntax :
# hacf -verify /etc/VRTSvcs/conf/config/
begin the VCS at the machine with changed important.Cf report :
# hastart
start VCS on other nodes inside the cluster.
Note : This may be finished in some other manner by using simply stopping VCS and leaving offerings jogging to limit the downtime. (hastop -all -pressure GAB, LLT and HAD)
Question: nine. What Is Gab, Llt And Had And What’s Their Functionalities ?
Answer:
GAB, LLT and HAD forms the simple constructing blocks of vcs functionality:
LLT (low latency shipping protocol) – LLT transmits the heartbeats over the interconnects. It is also used to distribute the inter gadget communique visitors equally among all of the interconnects.
GAB (Group membership services and atomic broadcast) – The group club provider part of GAB keeps the overall cluster club records by means of tracking the heartbeats sent over LLT interconnects. The atomic broadcast of cluster membership ensures that every node within the cluster has identical information approximately every aid and provider institution inside the cluster.
HAD (High Availability daemon) – the primary VCS engine which manages the retailers and provider institution. It is in flip monitored by way of a daemon named hashadow.
Logical Volume Manager (Linux) Interview Questions
Question 10. What Are The Various Gab Ports And Their Functionalities ?
Answer:
a : gab motive force
b : I/O fencing (to make certain statistics integrity)
d : ODM (Oracle Disk Manager)
f : CFS (Cluster File System)
h : VCS (VERITAS Cluster Server: high availability daemon, HAD)
o : VCSMM driving force (kernel module needed for Oracle and VCS interface)
q : QuickLog daemon
v : CVM (Cluster Volume Manager)
w : vxconfigd (module for cvm)
Question 11. How To Check The Status Of Various Gab Ports On The Cluster Nodes?
Answer:
To test the reputation of GAB ports on diverse nodes :
# gabconfig -a
Unix/Linux Interview Questions
Question 12. Whats The Maximum Number Of Llt Links (consisting of High And Low Priority) Can A Cluster Have ?
Answer:
A cluster can have a most of eight LLT hyperlinks including high and low precedence LLT hyperlinks.
Red Hat Linux System Administration Interview Questions
Question thirteen. How To Check The Detailed Status Of Llt Links ?
Answer:
The command to test certain LLT popularity is :
# lltstat -nvv
Question: 14. What Are The Various Llt Configuration Files And Their Function ?
Answer:
LLT uses /and so forth/llttab to set the configuration of the LLT interconnects.
# cat /and so forth/llttab
set-node node01
set-cluster 02
hyperlink nxge1 /dev/nxge1 – ether – –
hyperlink nxge2 /dev/nxge2 – ether – –
link-lowpri /dev/nxge0 – ether – –
Here, set-cluster -> precise cluster range assigned to the whole cluster [ can have a value ranging between 0 to (64k – 1) ]. It must be specific throughout the organisation.
Set-node -> a unique wide variety assigned to each node within the cluster. Here the name node01 has a corresponding particular node range within the file /and many others/llthosts. It can variety from zero to 31.
Another configuration record utilized by LLT is – /etc/llthosts. It has the cluster-huge particular node number and nodename as follows:
# cat /etc/llthosts
zero node01
1 node02
LLT has an any other elective configuration file : /and so on/VRTSvcs/conf/sysname. It includes brief names for VCS to refer. It can be utilized by VCS to eliminate the dependency on OS hostnames.
Question: 15. What Are Various Gab Configuration Files And Their Function ?
Answer:
The record /etc/gabtab carries the command to start the GAB.
# cat /and so forth/gabtab
/sbin/gabconfig -c -n four
right here -n four –> number of nodes that must be speaking a good way to start VCS.
Windows Clustering Interview Questions
Question 16. How To Start/stop Gab?
Answer:
The instructions to begin and prevent GAB are :
# gabconfig -c (begin GAB)
# gabconfig -U (stop GAB)
Question: 17. How To Start/forestall Llt?
Answer:
The commands to forestall and begin LLT are :
# lltconfig -c -> start LLT
# lltconfig -U -> stop LLT (GAB needs to stopped first)
Solaris Administrator Interview Questions
Question 18. What’s A Gab Seeding And Why Manual Gab Seeding Is Required ?
Answer:
The GAB configuration document /and so on/gabtab defines the minimal variety of nodes that ought to be speaking for the cluster to start. This is called as GAB seeding.
In case we don’t have enough range of nodes to begin VCS [ may be due to a maintenance activity ], but should do it in any case, then we’ve do what’s called as manual seeding with the aid of firing below command on every of the nodes.
# gabconfig -c -x
Solaris Interview Questions
Question 19. How To Start Had Or Vcs ?
Answer:
To start HAD or VCS on all nodes within the cluster, the hastart command need to be run on all nodes individually.
# hastart
Question: 20. What Are The Various Ways To Stop Had Or Vcs Cluster ?
Answer:
In standard, to feature a service group named SG with 2 nodes (node01 and node02) :
haconf –makerw
hagrp –add SG
hagrp –regulate SG SystemList node01 0 node02 1
hagrp –regulate SG AutoStartList node02
haconf –dump -makero
Volumetric Analysis Interview Questions
Question 21. How To Check The Configuration Of A Service Group – Sg ?
Answer:
To see the service institution configuration :
# hagrp -show SG
Question: 22. How To Bring Service Group Online/offline ?
Answer:
To on-line/offline the service organization on a selected node :
# hagrp -online [service-group] -sys [node] (Online the SG on a specific node)
# hagrp -offline [service-group] -sys [node] (Offline the SG on specific node)
The -any choice when used rather than the node name, brings the SG on line/offline primarily based on SG’s failover policy.
# hagrp -on-line [service-group] -any
# hagrp -offline [service-group] -any
Question: 23. How To Switch Service Groups ?
Answer:
The command to switch the carrier organization to goal node :
# hagrp -switch [service-group] -to [target-node]
Red Hat Certified Engineer (RHCE) Interview Questions
Question 24. How To Freeze/unfreeze A Service Group And What Happens When You Do So ?
Answer:
When you freeze a service institution, VCS keeps to screen the service institution, but does not permit it or the resources underneath it to be taken offline or added on-line. Failover is likewise disable even if a resource faults. When you unfreeze the SG, it begin behaving within the regular manner.
To freeze/unfreeze a Service Group temporarily :
# hagrp -freeze [service-group]
# hagrp -unfreeze [service-group]
To freeze/unfreeze a Service Group constantly (across reboots) :
# hagrp -freeze -continual[service-group]
# hagrp -unfreeze [service-group] -continual
Communication failures : Jeopardy, break up mind
SSRS(SQL Server Reporting Services) Interview Questions
Question 25. Whats A Jeopardy Membership In Vcs Clusters?
Answer:
When a node in the cluster has most effective the final LLT link intact, the node paperwork a everyday membership with other nodes with which it has more than one LLT link active and a Jeopardy club with the node with which it has best one LLT hyperlink active.
Question: 26. How To Recover From A Jeopardy Membership ?
Answer:
To get over jeopardy, just restoration the failed hyperlink(s) and GAB robotically detects the brand new hyperlink(s) and the jeopardy club is removed from node.
ZFS Interview Questions
Question 27. Whats A Split Brain Condition ?
Answer:
Split mind takes place while all of the LLT hyperlinks fails concurrently. Here systems within the cluster fail to become aware of whether or not it’s far a machine failure or an interconnect failure. Each mini-cluster for this reason fashioned thinks that it’s far the most effective cluster thats lively in the meanwhile and tries to begin the carrier groups on the other mini-cluster which he suppose is down. Similar aspect occurs to the alternative mini-cluster and this may lead to a simultaneous get admission to to the garage and might cause facts corruption.
Logical Volume Manager (Linux) Interview Questions
Question 28. Whats The Difference Between Multinica And Multinicb Resource Types ?
Answer:
MultiNICA and IPMultiNIC:
supports lively/passive configuration.
Requires most effective 1 base IP (take a look at IP).
Does now not require to have all IPs inside the same subnet.
MultiNICB and IPMultiNICB:
supports active/lively configuration.
Faster failover than the MultiNICA.
Requires IP deal with for each interface.
Troubleshooting
Question 29. How To Flush A Service Group And When Its Required ?
Answer:
Flushing of a carrier organization is needed when, agents for the sources inside the carrier group seems suspended anticipating sources to be taken on-line/offline. Flushing a carrier organization clears any internal wait states and stops VCS from trying to carry assets on-line.
To flush the carrier organization SG at the cluster node, node01 :
# hagrp -flush [SG] -sys node01
Question: 30. How To Clear Resource Faults ?
Answer:
To clean a useful resource fault, we first must repair the underlying problem.
For chronic resources : Do now not do anything and watch for the next OfflineMonitorInterval (default – 300 seconds) for the aid to come to be on line.
For non-continual resources : Clear the fault and probe the resource on node01 :
# hares -clear [resource_name] -sys node01
# hares -probe [resource_name] -sys node01
Question: 31. How To Clear Resources With Admin_wait State ?
Answer:
If the ManageFaults characteristic of a provider organization is set to NONE, VCS does not take any automatic motion when it detects a resource fault. VCS places the aid into the ADMIN_WAIT kingdom and waits for administrative intervention.
To clean the resource in ADMIN_WAIT state without faulting carrier group :
# hares -probe [resource] -sys node01
To clean the aid in ADMIN_WAIT kingdom with the aid of changing the status to OFFLINEessential.Cf is the main configuration file for VCS and it is located in /etc/VRTSvcs/conf/config/.
Unix/Linux Interview Questions
Question 34. Which Command You Will Use To Check The Syntax Of The Main.Cf? Or How To Verify The Syntax Of Main.Cf Configuration File?
Answer:
hacf -verify /etc/VRTSvcs/conf/config
Question: 35. How Will You Check The Status Of Individual Resources Of Vcs Cluster? Or How To Check The Individual Resources Status In Vcs Cluster?
Answer:
hares –country
Question: 36. What Is Service Group In Vcs?
Answer:
Service group is made from resources and their links that you normally requires to hold the HA of utility.
Windows Clustering Interview Questions
Question 37. What Is The Use Of Halink Command? Or What Is Halink In Veritas Cluster?
Answer:
halink is used to hyperlink the dependencies of the sources.
Question: 38. What Is The Difference Between Switchover And Failover? Or What Is Switchover And Failover?
Answer:
Switchover is an guide challenge wherein as failover is computerized. You can switchover carrier group from on-line cluster node to offline cluster node in case of strength outage, hardware failure, time table shutdown and reboot. But the failover will failover the carrier institution to the alternative node when VCS heartbeat hyperlink down, broken, broken due to a few disaster or device hung.
Question: 39. What Is The Use Of Hagrp Command? Or How To Manage The Service Group In Vcs?
Answer:
hagrp is used for doing administrative moves on service businesses like on-line, offline, transfer etc.
Question: forty. How To Switchover The Service Group In Vcs? Or How To Move The Service Group From One Node To Other Node In Vcs?
Answer:
hagrp –switch -to nodename
Solaris Administrator Interview Questions
Question forty one. How To Online The Service Groups In Vcs? Or How To Bring The Service Online In Particular Node?
Answer:
hagrp –on line -sys nodename
Question: forty two. Shutdown Vcs Cluster But Keep The Services Up.
Answer:
hastop -all -force
Volumetric Analysis Interview Questions
Question 43. How To Check The Gab Status In Vcs Cluster? Or Confirm Vcs Has Shut Down On Each System?
Answer:
gabconfig -a
Question: 44. How To Shutdown Gab And Confirm It’s Down On Each System?
Answer:
gabconfig -U
gabconfig -a
Question forty five. How To Identify The Gab Kernel Module And Remove It From Each System In Linux?
Answer:
lsmod 46. How To Shutdown Llt On Each System In Vcs Cluster?
Answer:
lltconfig -U
Question: 47 grep llt
rmmod ltt
Question: forty eight. How To Unfreeze All Service Groups?
Answer:
haconf -makerw
hagrp -unfreeze
haconf -sell off -makero
Question: forty nine. What Is Jeopardy In Vcs? Or What Is Jeopardy State?
Answer:
The kingdom in which a node is lacking one of the two required heartbeat connections. When a node is going for walks with one heartbeat simplest (in jeopardy), VCS does no longer restart the packages on a brand new node. This action of disabling failover is a protection mechanism that prevents facts corruption.
Question: 50. What Is Split Brain In Vcs? Or What Is Split Brain Syndrome In Vcs Cluster?
Answer:
A cut up brain takes place when impartial structures configured in a cluster anticipate they have got unique get entry to to resource. This state of affairs can be induced when all cluster heartbeat links are simultaneously lost. Each cluster node will then mark the alternative cluster node as FAULTED. , normally resulting in facts corruption.
Question: 51. What Is The Cluster Log File For Vcs Cluster?
Answer:
/var/VRTSvcs/log/engine_A.Log14
Question: fifty two. Which Daemons Are Required For Ldap Server?
Answer:
slapd and slurpd
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