VXVM Interview Question and answers VXVM Interview Question and answers

1. Name the mandatory disk group in VxVM 3.5 ? How will you configure VxVM in

3.5 ?

ANS: rootdg is the mandatory disk group in VxVM 3.5, vxinstall is the command to

configure VxVM, It will create the disk groups, initializes the disks and adds them to the

group.

2. How will you create private and shared disk group using VxVM ?

ANS: For Private DG:

Command: vxdg init

For Shared DG:

Command: vxdg -s init < disk1 disk2 disk3 >

3. Which are the different layouts for volumes in VxVM ?

ANS: mirror, stripe, concat (default one), raid5, stripe-mirror, mirror-stripe.

4. What is the basic difference between private disk group and shared disk group ?

ANS: Private DG: The DG which is only visible for the host on which you have created it, if

the host is a part of cluster, the private DG will not be visible to the other cluster nodes.

Shared DG: The DG which is sharable and visible to the other cluster nodes.

5. How will you add new disk to the existing disk group ?

ANS: Run vxdiskadm command, which will open menu driven program to do various disk

operations, select add disks option or you can use another command vxdiskadd.

6. How will you grow/shrink the volume/file system ? What is the meaning of growby

and growto options ? What is the meaning on shrinkto and shrinkby options ?

ANS: vxassist command is used to do all volume administration, following is the description

and syntax.

Growby option: This is will grow your file system by adding new size to the existing file

system.

Growto option: This will grow your file system as per the new size. This WILL NOT ADD

new size to the existing one.

Shrinkby option: This will shrink your file system by reducing new size from existing file

system.

Shrinkto option: This will shrink your file system as per the new size. This WILL NOT

REDUCE the file system by reducing new size.

Command:

vxassist -g [growto, growby, shrinkto, shrinkby] length

7. How will you setup and unsetup disks explicitly using VxVM ?

ANS: You can use /etc/vx/bin/vxdiskunsetup to unsetup the disk, and /etc/vx/vxdisksetup to

setup the disk.

8. How will you list the disks, which are in different disk groups ?

ANS: vxdisk list is the command will list the disks from the DG which is currently imported,

you can check the same using vxprint command too. vxdisk -o alldgs list command list all

the disks which are in different dg's.

9. What is the private region in VxVM ?

ANS: Private region stores the structured VxVM information, it also stores the disk ID and

disk geometry. In short words it has metadata of the disk.

10. If, vxdisk list command gives you disks status as "error", what steps you will

follow to make the respective disks online ?

ANS: If you faced this issue because of fabric disconnection then simply do vxdisk

scandisks, otherwise unsetup the disk using using /etc/vx/bin/vxdiskunsetup and setup the

disks again using /etc/vx/bin/vxdisksetup, this will definitely help! [ /etc/vx/bin/vxdiskunsetup

will remove the private region from the disk and destroys data, backup the data before using

this option]

Veritas cluster services Interview questions 1. How do check the status of VERITAS Cluster Server aka VCS ?

Ans: hastatus –sum3

2. Which is the main config file for VCS and where it is located?

Ans: main.cf is the main configuration file for VCS and it is located in

/etc/VRTSvcs/conf/config.

3. Which command you will use to check the syntax of the main.cf?

Ans: hacf -verify /etc/VRTSvcs/conf/config

4. How will you check the status of individual resources of VCS cluster?

Ans: hares –state

5. What is the service group in VCS ?

Ans: Service group is made up of resources and their links which you normally requires to

maintain the HA of application.

6. What is the use of halink command ?

Ans: halink is used to link the dependencies of the resources

7. What is the difference between switchover and failover ?

Ans: Switchover is an manual task where as failover is automatic. You can switchover

service group from online cluster node to offline cluster node in case of power outage,

hardware failure, schedule shutdown and reboot. But the failover will failover the service

group to the other node when VCS heartbeat link down, damaged, broken because of some

disaster or system hung.

8. What is the use of hagrp command ?

Ans: hagrp is used for doing administrative actions on service groups like online, offline,

switch etc.

9. How to switchover the service group in VCS ?

Ans: hagrp –switch -to

10. How to online the service groups in VCS ?

Ans: hagrp –online -sy

Interview Questions with answers : Veritas Cluster Server  Admin on Wed Jul 08, 2009 5:55 pm

1. How do check the status of VERITAS Cluster Server aka VCS ?

Ans: hastatus –sum

2. Which is the main config file for VCS and where it is located?

Ans: main.cf is the main configuration file for VCS and it is located in

/etc/VRTSvcs/conf/config.

3. Which command you will use to check the syntax of the main.cf ?

Ans: hacf -verify /etc/VRTSvcs/conf/config

4. How will you check the status of individual resources of VCS cluster?

Ans: hares –state

5. What is the service group in VCS ?

Ans: Service group is made up of resources and their links which you normally requires to

maintain the HA of application.

6. What is the use of halink command ?

Ans: halink is used to link the dependencies of the resources

7. What is the difference between switchover and failover ?

Ans: Switchover is an manual task where as failover is automatic. You can switchover

service group from online cluster node to offline cluster node in case of power outage,

hardware failure, schedule shutdown and reboot. But the failover will failover the service

group to the other node when VCS heartbeat link down, damaged, broken because of some

disaster or system hung.

8. What is the use of hagrp command ?

Ans: hagrp is used for doing administrative actions on service groups like online, offline,

switch etc.

9. How to switchover the service group in VCS ?

Ans: hagrp –switch -to

10. How to online the service groups in VCS ?

Ans: hagrp –online -sys

UNIXLOG Archive for the ‘veritas volume manager’ Categorycfgadm:::Device being used by   VxVM leave a comment »root@abc>/> cfgadm -c unconfigure c1::dsk/c1t0d0cfgadm: Component system is busy, try again: failed to offline: /devices/ssm@0,0/pci@1c,700000/pci@1/SUNW,isptwo@4/sd@0,0Resource              Information——————  ————————-/dev/dsk/c1t0d0s2   Device being used by VxVM“cfgadm unconfigure” command fails here.

The way to resolve this is to disable the disks path from DMP control. Since there is only one path to this disk, the “-f” (for force) option needs to be used:

root@abc>/> vxdmpadm -f disable path=c1t0d0s2root@abc>/> vxdmpadm getsubpaths ctlr=c1NAME         STATE[A]   PATH-TYPE[M] DMPNODENAME  ENCLR-TYPE   ENCLR-NAME   ATTRS================================================================================c1t0d0s2     DISABLED     -          c1t0d0s2     Disk         Disk           -c1t6d0s2     ENABLED(A)   -          c1t6d0s2     Disk         Disk           -You can see the path now disabled from DMP.

root@abc>/> cfgadm -c unconfigure c1::dsk/c1t0d0cfgadm goes through fine.

root@abc>/>

Written by krishsubramanianNovember 3, 2010 at 1:40 pmPosted in Solaris, veritas volume manager

Rootdg corruption Server fails to   boot with one commentThere are times when one has to go through the cut… Server has a bad panic/power trip  and it corrupts the rootdg badly and the server is unable to boot with VxVM.   Here is a procedure to recover from the situation.

1. Boot from the cdrom or from the network

2. Mount the rootdisk.

3. Once mounted, disable the start up of VxVM.

- Edit /a/etc/system. Comment out the vx parameter as follow:*rootdev:/pseudo/vxio@0:0*set vxio:vol_rootdev_is_volume=1- cd /a/etc/vx/reconfig.d/state.d/- rm root-done- touch install-db- cp -p /a/etc/vfstab /a/etc/vfstab.withvm

- cp -p /a/etc/vfstab.prevm /a/etc/vfstab- init 64.  Ensure the server comes up without veritas starting up.

5. Manually start the veritas volume manager.

- vxiod set 10- ps -ef |grep vxconfigd. If vxconfigd is not running, then run “/usr/sbin/vxconfigd -m disable”- vxdctl mode.   Should see it is in disabled mode.- vxdctl init- vxdctl enable- vxdctl mode6. Check the diskgroups.

- vxdg list7. Deport the rootdg so that it does not come up again.

- vxdg deport rootdg8. Zero out private and public region partitions from the disks on the rootdg.

- format -d <c#t#d#>9. Once this is done, the disks should show as error.

- vxdisk list10. Re encapsulate the disk.

- cd /etc/vx/reconfig.d/state.d/- rm install-db- vxdiskadm. Option 2 to encapsulate the primary bootdisk- Reboot machine upon completed Option 2 above.11. Verify for the boot and all volumes coming up clean.

- vxprint -ht, to verify all the volume are enabled. If the volume not started, then run “vxvol -g groupname startall” to start the volume.- Revert back the /etc/vfstab.withvm to /etc/vfstab- mount all the volume and verify.12. Mirror to second bootdisk

- vxdiskadm. Option 1 to Add or initialize the second bootdisk- vxdiskadm. Option 6 to mirror the secondary bootdiskWritten by krishsubramanianMay 1, 2010 at 4:32 pmPosted in veritas volume manager

VxVM   Upgrade leave a comment »Lets look at VxVM Upgrade this week…

The setup is

a) Solaris 9b) VxVM 4.0 / VxDMP –> No powerpathc) Oracle databases.I upgraded to Storage Foundation 5.0 MP3.    The tech plan is as below:

1. Install the VRTSspt Package.  Down load the package from symantec website

2. Run the VRTSexplorer and keep the file at a safe location if you may need it in case you run in any issue.

3. Break the rootmirror

4. Unencapsulate the rootmirror.

# mount /dev/dsk/c0t1d0s0 /alt.root# cd /alt.root/etc# touch /alt.root/etc/vx/reconfig.d/state.d/install-dbrootdev:/pseudo/vxio@0:0set vxio:vol_rootdev_is_volume=1Remove the above lines from /alt.root/etc/system file

Make changes to /etc/vfstab to ensure the system boots from the mirror disk ( c#t#d#)

5. Boot the server from rootmirror and verify for the server coming up.

6. Boot again from the rootdisk.

7. Check for the pre-requiste packages. Solaris 9 for Storage Foundation need

SUNWcfcl,SUNWcfclr, SUNWcfclx packages and patch 114477-04.8. Install the packages first and then the patches.  Packages and patches can be downloaded from

http://www.sun.com/downloads

and choose A-Z downloads

9. Verify the pre-staged software is not corrupted and working fine. ( You can do this by doing a tar and keeping the software ready)

10. Ensure all applications/Databases  are shutdown and the file-systems are down.

11. Ensure all the apps/db’s  are umounted clean .

# echo “8192B.p S” | fsdb -F vxfs <Raw_Device> | grep cleanReceive: flags 0 mod 0 clean clean_value

Note: A clean_value value of 0x5a indicates the file system is clean, 0x3c incidates the file system is dirty, and 0×69 indicates the file system is dusty. A dusty file system has pending extended operations.

Note: If a file system is not clean, enter the following commands for that file system:

Enter: fsck -F vxfs filesystemEnter: mount -F vxfs [Block_Device] [mountpoint]Enter: umount [mountpoint]Note: This should complete any extended operations that were outstanding on the file system and unmount the file system cleanly.

12.  Run the upgrade_start -check

# /storage_foundation/scripts/upgrade_start -check-Note: this is a veritas check script that will check to see if this machine is eligible for upgrade.

13.Ensure that the root mirror is removed from rootdg.

# /sbin/vxdg –g rootdg –f rmdisk rootmirror14. Un encapsulate the rootdisk

Remove the following lines from /etc/systemrootdev:/pseudo/vxio@0:0set vxio:vol_rootdev_is_volume=1Prevent veritas from starting up.#/usr/bin/cd /etc/vx/reconfig.d/state.d#/usr/bin/rm root-done#/usr/bin/touch install-db15 . Deport all appdiskgroups.

16.  Reboot the node to single user mode.

17. Remove all packages that start with VRTS but for VRTSvlic.  Don’t remove the VRTSvlic packages.  I believe you can remove this as well, but I have not tried it myself.

# pkginfo | grep VRTS# pkgrm VRTSxxxx18. Install the Veritas 5.0 Software

# ./installerNote : Answer the questions and complete the installation.  Insome cases veritas may not start correctly and will require a reboot.

19. If you are upgrading from 4.0 or later the licenses should take of themselves.

20. Manually Encapsualte the rootdisk after upgrade.

# vxdiskadmChoose option 2 and give the root disk  for encapsulation.

21. Import the disk groups and mount the filesystems.

22. Ensure applications are working fine

23. Remirror the rootdrive follow standard procedures.

Written by krishsubramanianFebruary 13, 2010 at 4:50 pmPosted in veritas volume manager

Extending Filesystems in Sun Cluster   using   VxVM leave a comment »I did an activity to add LUNS to existing database file systems running sun Cluster 3.1, Solaris 9 OS with VxVM. The steps I followed are :

a) Get the LUN information from Storage  and update the sd.conf accordingly on both the servers

b) Make the LUNS Visible on the server. Run the command on both the nodes

#update_drv -f sdc) Verify for the LUNS present; # formatd) Configure emcpower devices. Run on both the servers.

# /etc/powermt config# /etc/powermt savee) Create the Sun Cluster DID devices. Run on both nodes if required.

# devfsadm# scgdevsf) Verify the sun Cluster DID devices. # scdidadm -Lg) Add the disks to veritas diskgroup ; # vxdiskadmh) Grow the FS

Written by krishsubramanianOctober 25, 2009 at 6:27 amPosted in Solaris, Sun cluster, veritas volume managerTagged with Sun cluster, Veritas

Identifying multiple paths for a disk under VxVM   control leave a comment »This is a routine task for people dealing with VERITAS volume manager. There are times when one need to confirm the number of paths for the disk.

This can be accomplished by the below command.

# vxdisk list <diskname>In this one can look at the numpaths value at the bottom of the output.

Written by krishsubramanianDecember 8, 2008 at 2:49 pmPosted in veritas volume manager

Mirroring an Empty volume under   VxVM leave a comment »If you are mirroring empty Veritas plexes, this post is for you.  Normally we would wait ensuring the plexes are in sync.  If the plex size is large, then the waiting time is more.  A workaround is

# vxassist -g <dgname> make testvol 1g layout=mirror init=active dgname01 dgname02init=active is the keyword here.

This should save lot of time.

Written by krishsubramanianNovember 14, 2008 at 12:09 pmPosted in veritas volume manager

Identifying and Replacing failed disks in   V880 leave a comment »

Hi, recently i ran in to a problem of failed disk with V880.  I wanted to make sure if the disk has indeed failed.  Server was running VxVM.   Did these commands to identify the disk failure.

V880 has internal FCAL loop.  So to identify that

#luxadm probeFound Enclosure:SUNWGS INT FCBPL   Name:LoopA   Node WWN:508002000011d7d8   Logical Path:/dev/es/ses0#luxadm display LoopA                SUNWGS INT FCBPL                 DISK STATUSSLOT   DISKS             (Node WWN)        0      On (O.K.)         2000002037f87099   1      On (O.K.)         2000002037f39796   2      On (Login failed)                        3      Not Installed                        4      Not Installed                        5      Not Installed                        6      Not Installed                    7      Not Installed                    8      Not Installed                    9      Not Installed                    10     Not Installed                    11     Not Installed                                    SUBSYSTEM STATUSFW Revision:9218   Box ID:0  Node WWN:508002000011d7d8   Enclosure Name:LoopASSC100′s – 0=Base Bkpln, 1=Base LoopB, 2=Exp Bkpln, 3=Exp LoopB    SSC100 #0:    O.K.(11.A)    SSC100 #1:    O.K.(11.A)    SSC100 #2:    Not Installed    SSC100 #3:    Not Installed          Temperature Sensors – 0 Base, 1 Expansion                                0:21ºC  1:Not InstalledHere we can identify the disk failure at the slot no 2.  This is a good way to identify the failed disk under internal FCAL loop.

Since its a VxvM disk, make sure its in failed was or removed state. 

# vxdisk list   DEVICE       TYPE      DISK         GROUP        STATUS   c1t0d0s2     sliced    rootdisk     rootdg       online   c1t1d0s2     sliced    disk01       rootdg       online   c1t1d0s2     sliced    –        -            online   -            -         disk02       rootdg       failed was:c1t2d0s2Run vxdiskadm option 4 to remove the disk for replacement.  After running vxdiskadm the output should look similar to this:

# vxdisk list   DEVICE       TYPE      DISK         GROUP        STATUS   c1t0d0s2     sliced    rootdisk     rootdg       online   c1t1d0s2     sliced    disk01       rootdg       online

   c1t2d0s2 sliced    -            -            online   -            -         disk02       rootdg       removed was:c1t2d0s21. Put the disk into offline state; # vxdisk offline c1t2d0s22. VxVM is ready for removal of the disk, run the luxadm offline to remove the WWN entries and device links for the failed drive ; # luxadm -e offline /dev/rdsk/c1t2d0s23. Do the luxadm to remove the device. ; #luxadm remove_device /dev/rdsk/c1t2d0s24. check the device file ; #devfsadm -C ; # ls -ld /dev/rdsk/c1t2d0*5. Replace the disk physically

6. Run the devfsadm ; # devfsadm7. verify with luxadm display ; # luxadm display LoopA8. label the disk ; use format and label

9. # vxdctl enable10. # vxdisk list ; you would see a new disk.11. Now use vxdiskadm option 5 to replace the disk.  Give yes to the access question.

12. Verify the sync ; # vxtask listThats it you should see the replaced disk doing just fine.

Written by krishsubramanianOctober 17, 2008 at 5:12 pmPosted in Servers, veritas volume manager

Veritas recovery   features leave a comment »In this post i will explain the volume recovery and disk group recovery in veritas volume manager.  As an admin, we may face situations where one deletes a volume accidentally or destroy a dg by mistake.  If we do not have configuration backups of the objects, we are in for some trouble.  In order to save our a** its always better to be proactive and do the objects backups.

From 3.5 MP3 ( if am correct) vxvm offers vxconfigbackup & vxconfigrestore options for automatic object backups.  vxconfigbackupd is a daemon which runs in the background and do upto date backups of all the disk group and the objects associated with it.   All the backups are stored in /etc/vx/cbr/bk/dgnamedirectory.  Whenever a configuration change occurs, vxconfigbackupd daemon updates the directories with the latest configuration.  One can also manually do the object backups using the vxconfigbackupcommand.  One can use the “-l” option to change the default location of the backups.vxconfigbackup -l /var/vxvmbackups datadgThis would update all the configuration backups to /var/vxvmbackups directory for datadg.   If we need to recover the configuration information for the entire datadg, we can use the vxconfigrestore option.  There can be situations where the configuration information is completely lost due to system outages or reboots./etc/vx/bin/vxconfigrestore -p /var/vxvmbackups datadg  # to precommit the changes/etc/vx/bin/vxconfigrestore -c /var/vxvmbackups datadg  # to commit the changesA vxprint output will give the confirmation

vxprint -g datadgI just explained how to go about backingup and recovering configuration data using the vxconfigbackup and vxconfigrestore options.  There may be situations when someone accidentally deletes the volume of a diskgroup.  In such situations, backups of individual object information will come in handy… You can schedule a cron to backup individual object configuration…

/usr/sbin/vxprint -rhmvps ${volume_name} > ${DIR_NAME}/${volume_name}.${DATE}using the backed up file and vxmake we can easily recover the deleted volume configuration…

vxmake -g <dgname> -d <file_name>Verify the recovery using vxprint ; vxprint -g datadg -hrtStart the volume ; vxvol -g <dgname> start <vol_name>Volume is ready to do I/O.  As with the case with any recovery options, these options should be experimented before using in the production setup.

Written by krishsubramanianAugust 19, 2008 at 7:03 amPosted in Recovery, veritas volume manager

Converting a volume from gen to   fsgen with 10 commentsThere might be situations where one has to convert a volume from gen type to fsgen type.  Before going any further on the topic lets see what really fsgen and gen mean.

fsgen assumes that the volume contains a filesystem while gen assumes there is no filesystem.   fsgen and gen volume types provide similar but not identical semantics for operations using the vxplex utility.  In particular fsgen usage type attempts to flush in-memory data cached for the filesystem residing on the volume.  For most file systems this is the calling of sync to attempt to flush all in-memory data to disk.   I believe it is for this reason we associate all volumes that are using filesystems to be of fsgen type.   vxassist uses fsgen as the default type, where as vxmake uses gen as the default type…

Conversion of volume from one usage type to other cannot be done on the fly, it requires a volume downtime.   Lets take a look at this output…

v simplevol gen ENABLED ACTIVE 8388608 SELECT -pl simplevol-01 simplevol ENABLED ACTIVE 8392167 CONCAT – RWsd simple01-01 simplevol-01 simple-01 0 8392167 0 c1t0d0 ENAAs you can see from the output, we have a gen volume named simplevol, we now need to convert this simplevol from gen to fsgen type.  These are the steps that needs to be followed.

1. vxprint -g dgname -rhmvps simplevol > simplevol.vxout2. open the file simplevol.vxout using your fav editor and change the use_type field alone from gen to fsgen.

3. save the file.  make sure you edit the use_type field alone…

4. Umount the filesystem  ; umount /simplevol5. stop the volume ; vxvol -g dgname stop simplevol6. remove the volume ; vxedit -g dgname -rf rm simplevol7. using vxmake rebuild the volume from the saved file ; vxmake -g dgname -d simplevol.vxout8. check the vxprint out; vxprint -g dgname -hrt ; check for the usage type; it would be fsgen9. start the volume; vxvol -g dgname start simplevol10. do a fsck for the volume; fsck -y /dev/vx/rdsk/dgname/simplevol11. mount the filesystem ; mount /simplevolYou are ready to perform I/O for the filesystem..