21⟩ Suppose You have a boot disk under svm, the machine fails to boot and remains in ok prompt? what could be the possible reason?
1) May be issue with /etc/system file
2) Root file system corrupted
3) Wrong entries in /etc/vfstab file
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22⟩ How to create a shared disk group in VxVM?
Creating shared dg form the existing dg’s
1) List all the dg available: #vxdg list
2) Find out the node that is master or slace using:
#vxdctl -c mode
3) Deport the disk groups to be shared: #vxdg deport
<dg name>
4) Import dgs to be shared: #vxdg -s import < dg
name> % Do this on master node
5) To check the shared disk groups: #vxdg list
23⟩ What is the difference between private and public regions in Veritas Volume manager?
Private Region: It has meta data regarding the disk. A
copy of the configuration database is copied to each
private region with the disk group. It keeps 5 copies of
the configuration database. It is configured as slice 3.
Once the private region is created it cannot be changed.
Public region: This is the area where all users’ data is
stored. Usually it is configured as slice 4.
24⟩ How to convert a volume from gen to fsgen? why should you do that?
1) #vxprint -g dgname -rhmvps filename >
filename.vxoutput
2) 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 /simplevol
5. stop the volume ; vxvol -g dgname stop simplevol
6. remove the volume ; vxedit -g dgname -rf rm simplevol
7. using vxmake rebuild the volume from the saved file ;
vxmake -g dgname -d simplevol.vxout
8. check the vxprint out; vxprint -g dgname -hrt ; check
for the usage type; it would be fsgen
9. start the volume; vxvol -g dgname start simplevol
10. do a fsck for the volume; fsck -
y /dev/vx/rdsk/dgname/simplevol
11. mount the filesystem ; mount /simplevol
gen assumes a volume does not contain filesystem and fsgen
assumes a volume contains a file system. Vxassist uses
fsgen as default type and vxmake uses gen as default type.
25⟩ How to identify multiple paths for a disk?
#vxdisk list <disk name>
26⟩ What is the difference between Vxdmp and EMC powerpath?
vxdmp: The way the load balancing done is using round
robin approach
EMC Power path: It does it by knowing which path is
least loaded.
Powerpath will fail back a path once it becomes available.
The older version of DMP that we were using on Solaris you
had to manually bring back the other path. This could have
just been the limitations of Solaris as well. We ran Power
path on AIX and DMP on SUN.
27⟩ Do you know vxdisk -o alldgs list o/p shows some disk groups in braces… What does that signify?
Those are shared disk groups.
28⟩ What are the various layouts that are available in VxVM?
1) Mirroring (RAID-1)
2) Striping (RAID-0)
3) Concatenation and Spanning
4) Striping plus Mirroring (Mirrored-stripe or RAID 0+1)
5) Mirroring plus Striping (Striped mirror, RAID 1+0, OR RAID-10)
6) RAID-5 (Striping with parity).
29⟩ What is a layered volume? How to create it using vxmake?
Using vxmake we need to build each object until we
create a volume and its very easy to use vxassist instead
vxmake.
1) Create subdisk ( # vxmake –g dg dgname sd sdname )
2) Create plex (#vxmake –g dgname plex sd=sdname )
3) Create volume (#vxmake –g dgname -U fsgen vol plex=plexname )
30⟩ How to quickly mirror a volume, if the volume is empty?
With DRL : #vxassist –g <diskgroup> make <vol name>
<length> layout=mirror, log <diskname> <diskname>
Without DRL : #vxassist –g <diskgroup> make <volname>
<length> layout=mirror, nolog <diskname> <diskname>
31⟩ How to grow a volume?
First check how much space you can increase using
#vxassist -g <diskgroup> maxgrow
After checking how much you can increase we can use the
below commands to increase volume
#vxassist -g <diskgroup> growby <volume> <len_to_grow_by>
or
#vxassist -g <diskgroup> growto <volume> <new_len>
32⟩ What is the difference between failing and failed disks?
Failing disk
1) It shows read/write errors in /var/adm/messages.
2) As the time passes we can see increased number of hard
and transport error when checkd by iostat -En.
3)We can see the disk available when format is used
Failed disk
1)It shows “ disk not responding to selection” message
2)It only shows the increased transport errors
3)Format command displays “ disk not available” message
33⟩ How to replace a failed disk in Veritas?
Can be removed using vxdiskadm and select option 5 (
To replace a failed disk)
23. Plex is in a disabled state. How will you recover? what
are the steps to follow?
Ans: 1) Place the plex in CLEAN state #vxmend -g dg
fix clean fix
2) To recover other plexes in a volume from CLEAN plex
#vxmend -g dg fix stale plex
3) Enable CLEAN plex # vxvol -g dg start volume
34⟩ What is the difference between detached and disassociate state of plexes?
Source: Symantec Docs
Detach State
Detaching a plex leaves the plex associated with its
volume, but prevents normal volume I/O from being directed
to the plex. This operation can be applied to plexes that
are enabled or disabled. The rules for performing the
detach depend upon the usage types of the volumes involved.
The operation does not apply to dissociated plexes.
Disassociate State
Dissociate each of the named plexes. Dissociating a plex
breaks the link between the plex and its volume. A
dissociated plex is inaccessible until it is reassociated,
which can be done either with vxplex att or with vxmake.
Any checks and synchronizations that apply to the det
operation also apply to the dis operation.
Plex dissociation is the normal means of unmirroring a
volume, or reducing the mirror count for a volume. To
support this use, -o rm can be used to dissociate and
remove the plex (and its associated subdisks) in the same
operation. This makes the space used by those subdisks
usable for new allocations (such as with vxassist or with
vxmake).
Plex dissociation can also be used for file system backups
of volumes that are normally mirrored. Plex devices are not
directly mountable, so the backup method described for the
det operation will not work if the backup program requires
a mounted file system. To support such backup programs, a
plex can be dissociated and can then be allocated to a new
volume, such as with the command:
vxmake -U gen vol volume plex=plex
The created volume can then be started and mounted for use
by the backup program.
35⟩ What is the boot process of VxVM?
During the solaris boot process once it reads
the /etc/system file and is supposed to boot from veritas
volumes below are the two lines that need to be placed
in /etc/system file such that it boot using veritas root
device.
1. rootdev:/pseudo/vxio@0:0
2. set vxio:vol_rootdev_is_volume=1
36⟩ What is the difference between SVM and VxVM? What would you recommend to your clients? why?
SVM
1)Comes by default with Solaris 9/10
2)We cannot shrink volume in SVM
VxVM
1) Third party software where we need to install it
2) We can shrink volume in VxVM
37⟩ What are the various clusters you have worked on?
Never worked on all but can give below answer if you
have worked on any of them:
1) Sun Cluster
2) Veritas cluster
3) HACMP – High Availability Cluster Multiprocesing
38⟩ Which cluster is better VCS or Sun cluster?
Depends on the taste of the guy and budget they have
to implement the cluster.
39⟩ Compare and contrast VCS and Sun Cluster?
Sun Cluster
1) Kernel-based – Fatser in failure detection
2) It runs only on Solaris systems ( Platform dependent)
Veritas Cluster
1)Software based
2)Works on multiple OS ( Platform independent)
40⟩ How to start VCS service? What are the configuration files in VCS?
To start an agent: #haagent - start agentname -sys
To start cluster : #hastart
Configuration file: /etc/VRTSvcs/conf/config/main.cf
