Sunil's Blog

How to remove UEK (unbreakable enterprise kernel)

Check all the kernel’s installed

[root@oel5 ~]# rpm -qa | grep kernel 
kernel-devel-2.6.18-398.el5
kernel-uek-firmware-2.6.39-400.215.10.el5uek
kernel-uek-2.6.39-400.215.10.el5uek
kernel-uek-devel-2.6.39-400.215.10.el5uek
kernel-headers-2.6.18-398.el5
kernel-uek-2.6.39-400.250.6.el5uek
kernel-uek-devel-2.6.39-400.250.6.el5uek
kernel-2.6.18-398.el5
kernel-uek-firmware-2.6.39-400.250.6.el5uek

[root@oel5 ~]# rpm -qa | grep kernel

kernel-devel-2.6.18-398.el5

kernel-uek-firmware-2.6.39-400.215.10.el5uek

kernel-uek-2.6.39-400.215.10.el5uek

kernel-uek-devel-2.6.39-400.215.10.el5uek

kernel-headers-2.6.18-398.el5

kernel-uek-2.6.39-400.250.6.el5uek

kernel-uek-devel-2.6.39-400.250.6.el5uek

kernel-2.6.18-398.el5

kernel-uek-firmware-2.6.39-400.250.6.el5uek

Check current kernel in use.

[root@oel5 ~]# uname -r
2.6.39-400.250.6.el5uek

1 2	[root@oel5 ~]# uname -r 2.6.39-400.250.6.el5uek

remove uek kernel using yum command

[root@oel5 ~]# yum remove kernel-uek-2.3.39-400*
Loaded plugins: rhnplugin, security
This system is not registered with ULN.
You can use up2date --register to register.
ULN support will be disabled.
Setting up Remove Process
Resolving Dependencies
--> Running transaction check
---> Package kernel-uek.x86_64 0:2.6.39-400.215.10.el5uek set to be erased
--> Processing Dependency: kernel-uek >= 2.6.32-100.0.19 for package: oracle-linux
--> Processing Dependency: kernel-uek >= 2.6.32 for package: oracle-validated
---> Package kernel-uek.x86_64 0:2.6.39-400.250.6.el5uek set to be erased
---> Package kernel-uek-devel.x86_64 0:2.6.39-400.215.10.el5uek set to be erased
---> Package kernel-uek-devel.x86_64 0:2.6.39-400.250.6.el5uek set to be erased
---> Package kernel-uek-firmware.noarch 0:2.6.39-400.215.10.el5uek set to be erased
---> Package kernel-uek-firmware.noarch 0:2.6.39-400.250.6.el5uek set to be erased
--> Running transaction check
---> Package oracle-linux.noarch 0:5.0.0-9.el5 set to be erased
---> Package oracle-validated.x86_64 0:1.1.0-20.el5 set to be erased
--> Finished Dependency Resolution

Dependencies Resolved

===============================================================================================
 Package                   Arch         Version                          Repository       Size
===============================================================================================
Removing:
 kernel-uek                x86_64       2.6.39-400.215.10.el5uek         installed       104 M
 kernel-uek                x86_64       2.6.39-400.250.6.el5uek          installed       104 M
 kernel-uek-devel          x86_64       2.6.39-400.215.10.el5uek         installed        55 M
 kernel-uek-devel          x86_64       2.6.39-400.250.6.el5uek          installed        55 M
 kernel-uek-firmware       noarch       2.6.39-400.215.10.el5uek         installed       5.0 M
 kernel-uek-firmware       noarch       2.6.39-400.250.6.el5uek          installed       5.0 M
Removing for dependencies:
 oracle-linux              noarch       5.0.0-9.el5                      installed        0.0 
 oracle-validated          x86_64       1.1.0-20.el5                     installed        46 k

Transaction Summary
===============================================================================================
Remove        8 Package(s)
Reinstall     0 Package(s)
Downgrade     0 Package(s)

Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing        : kernel-uek-firmware                                                     1/8 
  Erasing        : kernel-uek-devel                                                        2/8 
  Erasing        : kernel-uek-firmware                                                     3/8 
  Erasing        : kernel-uek                                                              4/8 
  Erasing        : oracle-validated                                                        5/8 
  Erasing        : kernel-uek-devel                                                        6/8 
  Erasing        : oracle-linux                                                            7/8 
  Erasing        : kernel-uek                                                              8/8 

Removed:
  kernel-uek.x86_64 0:2.6.39-400.215.10.el5uek                                                 
  kernel-uek.x86_64 0:2.6.39-400.250.6.el5uek                                                  
  kernel-uek-devel.x86_64 0:2.6.39-400.215.10.el5uek                                           
  kernel-uek-devel.x86_64 0:2.6.39-400.250.6.el5uek                                            
  kernel-uek-firmware.noarch 0:2.6.39-400.215.10.el5uek                                        
  kernel-uek-firmware.noarch 0:2.6.39-400.250.6.el5uek                                         

Dependency Removed:
  oracle-linux.noarch 0:5.0.0-9.el5           oracle-validated.x86_64 0:1.1.0-20.el5          

Complete!
[root@oel5 ~]#

[root@oel5 ~]# yum remove kernel-uek-2.3.39-400*

Loaded plugins: rhnplugin, security

This system is not registered with ULN.

You can use up2date --register to register.

ULN support will be disabled.

Setting up Remove Process

Resolving Dependencies

--> Running transaction check

---> Package kernel-uek.x86_64 0:2.6.39-400.215.10.el5uek set to be erased

--> Processing Dependency: kernel-uek >= 2.6.32-100.0.19 for package: oracle-linux

--> Processing Dependency: kernel-uek >= 2.6.32 for package: oracle-validated

---> Package kernel-uek.x86_64 0:2.6.39-400.250.6.el5uek set to be erased

---> Package kernel-uek-devel.x86_64 0:2.6.39-400.215.10.el5uek set to be erased

---> Package kernel-uek-devel.x86_64 0:2.6.39-400.250.6.el5uek set to be erased

---> Package kernel-uek-firmware.noarch 0:2.6.39-400.215.10.el5uek set to be erased

---> Package kernel-uek-firmware.noarch 0:2.6.39-400.250.6.el5uek set to be erased

--> Running transaction check

---> Package oracle-linux.noarch 0:5.0.0-9.el5 set to be erased

---> Package oracle-validated.x86_64 0:1.1.0-20.el5 set to be erased

--> Finished Dependency Resolution

Dependencies Resolved

===============================================================================================

Package Arch Version Repository Size

===============================================================================================

Removing:

kernel-uek x86_64 2.6.39-400.215.10.el5uek installed 104 M

kernel-uek x86_64 2.6.39-400.250.6.el5uek installed 104 M

kernel-uek-devel x86_64 2.6.39-400.215.10.el5uek installed 55 M

kernel-uek-devel x86_64 2.6.39-400.250.6.el5uek installed 55 M

kernel-uek-firmware noarch 2.6.39-400.215.10.el5uek installed 5.0 M

kernel-uek-firmware noarch 2.6.39-400.250.6.el5uek installed 5.0 M

Removing for dependencies:

oracle-linux noarch 5.0.0-9.el5 installed 0.0

oracle-validated x86_64 1.1.0-20.el5 installed 46 k

Transaction Summary

===============================================================================================

Remove 8 Package(s)

Reinstall 0 Package(s)

Downgrade 0 Package(s)

Is this ok [y/N]: y

Downloading Packages:

Running rpm_check_debug

Running Transaction Test

Finished Transaction Test

Transaction Test Succeeded

Running Transaction

Erasing : kernel-uek-firmware 1/8

Erasing : kernel-uek-devel 2/8

Erasing : kernel-uek-firmware 3/8

Erasing : kernel-uek 4/8

Erasing : oracle-validated 5/8

Erasing : kernel-uek-devel 6/8

Erasing : oracle-linux 7/8

Erasing : kernel-uek 8/8

Removed:

kernel-uek.x86_64 0:2.6.39-400.215.10.el5uek

kernel-uek.x86_64 0:2.6.39-400.250.6.el5uek

kernel-uek-devel.x86_64 0:2.6.39-400.215.10.el5uek

kernel-uek-devel.x86_64 0:2.6.39-400.250.6.el5uek

kernel-uek-firmware.noarch 0:2.6.39-400.215.10.el5uek

kernel-uek-firmware.noarch 0:2.6.39-400.250.6.el5uek

Dependency Removed:

oracle-linux.noarch 0:5.0.0-9.el5 oracle-validated.x86_64 0:1.1.0-20.el5

Complete!

[root@oel5 ~]#

[root@oel5 ~]# reboot

1	[root@oel5 ~]# reboot

[root@oel5 ~]# uname -r
2.6.18-398.el5

1 2	[root@oel5 ~]# uname -r 2.6.18-398.el5

now my kernel is downgraded to 2.6.18-398.el5.

please feel free to write me at sunil@sunilthetechfreak.com

how to restore OCR after complete loss of single OCR diskgroup

crs daemon was not able to start as my ocr diskgroup was not mounted. I logged in to asm instance.

[oracle@racnode1 ~]$ . oraenv

ORACLE_SID = [oracle] ? +ASM1

The Oracle base for ORACLE_HOME=/u01/app/11.2.0/grid is /u01/app/oracle

[oracle@racnode1 ~]$ sqlplus / as sysasm

 

SQL*Plus: Release 11.2.0.1.0 Production on Sun Jul 19 23:26:52 2015

 

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

 

 

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Real Application Clusters and Automatic Storage Management options

 

SQL> alter diskgroup CRS mount;

alter diskgroup CRS mount

*

ERROR at line 1:

ORA-15032: not all alterations performed

ORA-15130: diskgroup "CRS" is being dismounted

ORA-15066: offlining disk "CRS_0000" may result in a data loss

[oracle@racnode1 ~]$ . oraenv

ORACLE_SID = [oracle] ? +ASM1

The Oracle base for ORACLE_HOME=/u01/app/11.2.0/grid is /u01/app/oracle

[oracle@racnode1 ~]$ sqlplus / as sysasm

SQL*Plus: Release 11.2.0.1.0 Production on Sun Jul 19 23:26:52 2015

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Real Application Clusters and Automatic Storage Management options

SQL> alter diskgroup CRS mount;

alter diskgroup CRS mount

ERROR at line 1:

ORA-15032: not all alterations performed

ORA-15130: diskgroup "CRS" is being dismounted

ORA-15066: offlining disk "CRS_0000" may result in a data loss

But i was able to mount my other diskgroups

SQL> alter diskgroup DATA mount;

Diskgroup altered.

 

SQL> alter diskgroup FRA mount;

 

Diskgroup altered.

SQL> alter diskgroup DATA mount;

Diskgroup altered.

SQL> alter diskgroup FRA mount;

Diskgroup altered.

also checked using asmcmd lsdg –discovery command

SQL> quit

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Real Application Clusters and Automatic Storage Management options

[oracle@racnode1 ~]$ asmcmd lsdg --discovery

State       Type    Rebal  Sector  Block       AU  Total_MB  Free_MB  Req_mir_free_MB  Usable_file_MB  Offline_disks  Voting_files  Name

DISMOUNTED          N         512   4096        0         0        0                0               0              0             N  CRS/

MOUNTED     EXTERN  N         512   4096  1048576     15359    13678                0           13678              0             N  DATA/

MOUNTED     EXTERN  N         512   4096  1048576     15359    15001                0           15001              0             N  FRA/

SQL> quit

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Real Application Clusters and Automatic Storage Management options

[oracle@racnode1 ~]$ asmcmd lsdg --discovery

State Type Rebal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name

DISMOUNTED N 512 4096 0 0 0 0 0 0 N CRS/

MOUNTED EXTERN N 512 4096 1048576 15359 13678 0 13678 0 N DATA/

MOUNTED EXTERN N 512 4096 1048576 15359 15001 0 15001 0 N FRA/

came to know after checking alertlog CRS diskgroup had corrupted block.

Diskgroup used for OCR is:CRS

NOTE: cache registered group CRS number=1 incarn=0x4d38a200

NOTE: cache began mount (first) of group CRS number=1 incarn=0x4d38a200

NOTE: Assigning number (1,0) to disk (/dev/oracleasm/disks/CRS)

NOTE: start heartbeating (grp 1)

kfdp_query(CRS): 3

Mon Jul 20 13:30:17 2015

kfdp_queryBg(): 3

NOTE: cache opening disk 0 of grp 1: CRS_0000 path:/dev/oracleasm/disks/CRS

NOTE: F1X0 found on disk 0 au 2 fcn 0.0

NOTE: cache mounting (first) external redundancy group 1/0x4D38A200 (CRS)

Mon Jul 20 13:30:17 2015

* allocate domain 1, invalid = TRUE

Mon Jul 20 13:30:17 2015

NOTE: attached to recovery domain 1

WARNNING: cache read a corrupted block group=CRS fn=1 blk=3 from disk 0

NOTE: a corrupted block from group CRS was dumped to /u01/app/11.2.0/grid/log/diag/asm/+asm/+ASM1/trace/+ASM1_ora_6709.trc

WARNNING: cache read(retry) a corrupted block group=CRS fn=1 blk=3 from disk 0

ERROR: cache failed to read group=CRS fn=1 blk=3 from disk(s): 0 CRS_0000

ORA-15196: invalid ASM block header [kfc.c:23924] [endian_kfbh] [1] [3] [0 != 1]

ORA-15196: invalid ASM block header [kfc.c:23908] [endian_kfbh] [1] [3] [0 != 1]

ORA-15196: invalid ASM block header [kfc.c:23924] [endian_kfbh] [1] [3] [0 != 1]

ORA-15196: invalid ASM block header [kfc.c:23908] [endian_kfbh] [1] [3] [0 != 1]

System State dumped to trace file /u01/app/11.2.0/grid/log/diag/asm/+asm/+ASM1/trace/+ASM1_ora_6709.trc

NOTE: AMDU dump of disk group CRS created at /u01/app/11.2.0/grid/log/diag/asm/+asm/+ASM1/trace

NOTE: cache initiating offline of disk 0 group CRS

NOTE: process 6709 initiating offline of disk 0.3915928308 (CRS_0000) with mask 0x7e in group 1

WARNING: Disk CRS_0000 in mode 0x7f is now being taken offline

NOTE: initiating PST update: grp = 1, dsk = 0/0xe96852f4, mode = 0x15

Diskgroup used for OCR is:CRS

NOTE: cache registered group CRS number=1 incarn=0x4d38a200

NOTE: cache began mount (first) of group CRS number=1 incarn=0x4d38a200

NOTE: Assigning number (1,0) to disk (/dev/oracleasm/disks/CRS)

NOTE: start heartbeating (grp 1)

kfdp_query(CRS): 3

Mon Jul 20 13:30:17 2015

kfdp_queryBg(): 3

NOTE: cache opening disk 0 of grp 1: CRS_0000 path:/dev/oracleasm/disks/CRS

NOTE: F1X0 found on disk 0 au 2 fcn 0.0

NOTE: cache mounting (first) external redundancy group 1/0x4D38A200 (CRS)

Mon Jul 20 13:30:17 2015

* allocate domain 1, invalid = TRUE

Mon Jul 20 13:30:17 2015

NOTE: attached to recovery domain 1

WARNNING: cache read a corrupted block group=CRS fn=1 blk=3 from disk 0

NOTE: a corrupted block from group CRS was dumped to /u01/app/11.2.0/grid/log/diag/asm/+asm/+ASM1/trace/+ASM1_ora_6709.trc

WARNNING: cache read(retry) a corrupted block group=CRS fn=1 blk=3 from disk 0

ERROR: cache failed to read group=CRS fn=1 blk=3 from disk(s): 0 CRS_0000

ORA-15196: invalid ASM block header [kfc.c:23924] [endian_kfbh] [1] [3] [0 != 1]

ORA-15196: invalid ASM block header [kfc.c:23908] [endian_kfbh] [1] [3] [0 != 1]

ORA-15196: invalid ASM block header [kfc.c:23924] [endian_kfbh] [1] [3] [0 != 1]

ORA-15196: invalid ASM block header [kfc.c:23908] [endian_kfbh] [1] [3] [0 != 1]

System State dumped to trace file /u01/app/11.2.0/grid/log/diag/asm/+asm/+ASM1/trace/+ASM1_ora_6709.trc

NOTE: AMDU dump of disk group CRS created at /u01/app/11.2.0/grid/log/diag/asm/+asm/+ASM1/trace

NOTE: cache initiating offline of disk 0 group CRS

NOTE: process 6709 initiating offline of disk 0.3915928308 (CRS_0000) with mask 0x7e in group 1

WARNING: Disk CRS_0000 in mode 0x7f is now being taken offline

NOTE: initiating PST update: grp = 1, dsk = 0/0xe96852f4, mode = 0x15

[root@racnode1 trace]# ocrcheck

PROT-602: Failed to retrieve data from the cluster registry

PROC-26: Error while accessing the physical storage ASM error [SLOS: cat=8, opn=kgfolclcpi1, dep=208, loc=kgfokge

AMDU-00208: File directory block not found. Cannot extract file CRS.255

AMDU-00209: Corrupt block found: Disk N0004 AU [0] block [3] type [3]

AMDU-00201: Disk N

] [8]

[root@racnode1 trace]# ocrcheck

PROT-602: Failed to retrieve data from the cluster registry

PROC-26: Error while accessing the physical storage ASM error [SLOS: cat=8, opn=kgfolclcpi1, dep=208, loc=kgfokge

AMDU-00208: File directory block not found. Cannot extract file CRS.255

AMDU-00209: Corrupt block found: Disk N0004 AU [0] block [3] type [3]

AMDU-00201: Disk N

] [8]

referring doc id 1062983.1 i was able to restore ocr to a new disk with same diskgroup name

stop cluster on all nodes
crsctl stop crs -f

#delete the corrupted disk
oracleasm deletedisk CRS

# formatted new disk  
fdisk /dev/sdf
oracleasm createdisk CRS /dev/sdf1
oracleasm scandisks
oracleasm listdisks

start cluster in exclusive mode
crsctl start crs -excl

stop CRS daemon
crsctl stop res ora.crsd -init

login with grid user
sqlplus / as sysasm

create diskgroup CRS external redundancy disk '/dev/oracleasm/disk/CRS' attribute 'COMPATIBLE.ASM'='11.2';

after diskgroup is created
quit from sql

login as root user 
locate the ocr backup under $GRIDHOME/CDATA/raccluster

ocrconfig -restore backup00.ocr

#no message is displayed if restored successfully

start the crs daemon
crsctl start res ora.crsd -init

recreate the voting file
crsctl replace votedisk +CRS
you should receive voting file successfully replaced

create pfile for asm instance only if your spfile was located in crs disk group

copy the non default parameter from the alert log located under $GRID_HOME/log/nodename/alertnodename.log

vi /tmp/asm_pfile.ora


*.large_pool_size          = 12M
*.instance_type            = "asm"
*.remote_login_passwordfile= "EXCLUSIVE"
*.asm_diskstring           = "/dev/oracleasm/disks"
*.asm_power_limit          = 1
*.diagnostic_dest          = "/u01/app/oracle"

save and close

as grid user login to asm instance
sys / as sysasm

create spfile='+CRS' from pfile='/tmp/asm_pfile.ora';

exit

shutdown crs

login as root and shutdown crs

crsctl stop crs -f

scan asm disk on all nodes
oracleasm scandisks

startup crs on all nodes
crsctl start crs

and check if everything is working fine
crsctl check cluster -all

stop cluster on all nodes

crsctl stop crs -f

#delete the corrupted disk

oracleasm deletedisk CRS

# formatted new disk

fdisk /dev/sdf

oracleasm createdisk CRS /dev/sdf1

oracleasm scandisks

oracleasm listdisks

start cluster in exclusive mode

crsctl start crs -excl

stop CRS daemon

crsctl stop res ora.crsd -init

sqlplus / as sysasm

create diskgroup CRS external redundancy disk '/dev/oracleasm/disk/CRS' attribute 'COMPATIBLE.ASM'='11.2';

after diskgroup is created

quit from sql

locate the ocr backup under $GRIDHOME/CDATA/raccluster

ocrconfig -restore backup00.ocr

#no message is displayed if restored successfully

start the crs daemon

crsctl start res ora.crsd -init

recreate the voting file

crsctl replace votedisk +CRS

you should receive voting file successfully replaced

create pfile for asm instance only if your spfile was located in crs disk group

copy the non default parameter from the alert log located under $GRID_HOME/log/nodename/alertnodename.log

vi /tmp/asm_pfile.ora

*.large_pool_size = 12M

*.instance_type = "asm"

*.remote_login_passwordfile= "EXCLUSIVE"

*.asm_diskstring = "/dev/oracleasm/disks"

*.asm_power_limit = 1

*.diagnostic_dest = "/u01/app/oracle"

save and close

as grid user login to asm instance

sys / as sysasm

create spfile='+CRS' from pfile='/tmp/asm_pfile.ora';

exit

shutdown crs

crsctl stop crs -f

scan asm disk on all nodes

oracleasm scandisks

startup crs on all nodes

crsctl start crs

and check if everything is working fine

crsctl check cluster -all

please feel free to ask me at sunil@sunilthetechfreak.com

Generic failure interacting with CRS while using asmca utility to mount diskgroup

While i was mounting diskgroup using asmca utility. I got the below error

I just logged in sqlplus / as sysasm and issued the below command

alter diskgroup DATA mount;

1	alter diskgroup DATA mount;

the issue was resolved and i was able to create database.

Hope that helps

How to extend root partition on linux using lvm

Here my partition is on lvm (Logical volume manager)

[root@racnode2 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                       16G   13G  1.6G  90% /
/dev/sda1             487M   41M  421M   9% /boot
tmpfs                1004M  176M  828M  18% /dev/shm
.host:/               1.9T  1.1T  821G  56% /mnt/hgfs

[root@racnode2 ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup00-LogVol00

16G 13G 1.6G 90% /

/dev/sda1 487M 41M 421M 9% /boot

tmpfs 1004M 176M 828M 18% /dev/shm

.host:/ 1.9T 1.1T 821G 56% /mnt/hgfs

Check physical volume

[root@racnode2 ~]# pvs
  PV         VG         Fmt  Attr PSize  PFree
  /dev/sda2  VolGroup00 lvm2 a--  19.50G    0

[root@racnode2 ~]# pvs

PV VG Fmt Attr PSize PFree

/dev/sda2 VolGroup00 lvm2 a-- 19.50G 0

Check Volume group

[root@racnode2 ~]# vgs
  VG         #PV #LV #SN Attr   VSize  VFree
  VolGroup00   1   2   0 wz--n- 19.50G    0

[root@racnode2 ~]# vgs

VG #PV #LV #SN Attr VSize VFree

VolGroup00 1 2 0 wz--n- 19.50G 0

here you can see i have only one disk sda

[root@racnode2 by-path]# ll /dev/disk/by-path
total 0
lrwxrwxrwx 1 root root  9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-0 -> ../../sdb
lrwxrwxrwx 1 root root 10 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-0-part1 -> ../../sdb1
lrwxrwxrwx 1 root root  9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-1 -> ../../sdc
lrwxrwxrwx 1 root root 10 Jul 13 17:02 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-1-part1 -> ../../sdc1
lrwxrwxrwx 1 root root  9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-2 -> ../../sdd
lrwxrwxrwx 1 root root 10 Jul 13 17:02 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-2-part1 -> ../../sdd1
lrwxrwxrwx 1 root root  9 Jul 13 16:51 pci-0000:00:07.1-ide-0:0 -> ../../hdc
lrwxrwxrwx 1 root root  9 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0 -> ../../sda
lrwxrwxrwx 1 root root 10 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0-part2 -> ../../sda2

[root@racnode2 by-path]# ll /dev/disk/by-path

total 0

lrwxrwxrwx 1 root root 9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-0 -> ../../sdb

lrwxrwxrwx 1 root root 10 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-0-part1 -> ../../sdb1

lrwxrwxrwx 1 root root 9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-1 -> ../../sdc

lrwxrwxrwx 1 root root 10 Jul 13 17:02 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-1-part1 -> ../../sdc1

lrwxrwxrwx 1 root root 9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-2 -> ../../sdd

lrwxrwxrwx 1 root root 10 Jul 13 17:02 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-2-part1 -> ../../sdd1

lrwxrwxrwx 1 root root 9 Jul 13 16:51 pci-0000:00:07.1-ide-0:0 -> ../../hdc

lrwxrwxrwx 1 root root 9 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0 -> ../../sda

lrwxrwxrwx 1 root root 10 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0-part1 -> ../../sda1

lrwxrwxrwx 1 root root 10 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0-part2 -> ../../sda2

Now i will add new disk to my virtual machine
right click on the virtual machine and select settings
then click on add select hard disk from the above list
click on next
select scsi and click next
create new disk and click next
specify disk capacity in my case i am adding 15g and click on split virtual disk into multiple files and click next
provide the diskname.vmdk and specify the location where it should be saved and click on finish
click on ok to exit the virtual machine settings

no need to restart the running virtual machine just type the below command so that system scans the new disk

[root@racnode2 /]# echo "- - -" > /sys/class/scsi_host/host0/scan

1	[root@racnode2 /]# echo "- - -" > /sys/class/scsi_host/host0/scan

new disk is added /dev/sde

[root@racnode2 /]# ll /dev/disk/by-path/
total 0
lrwxrwxrwx 1 root root  9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-0 -> ../../sdb
lrwxrwxrwx 1 root root 10 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-0-part1 -> ../../sdb1
lrwxrwxrwx 1 root root  9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-1 -> ../../sdc
lrwxrwxrwx 1 root root 10 Jul 13 17:02 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-1-part1 -> ../../sdc1
lrwxrwxrwx 1 root root  9 Jul 13 16:52 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-2 -> ../../sdd
lrwxrwxrwx 1 root root 10 Jul 13 17:02 ip-sunil-pc:3260-iscsi-iqn.2008-08.com.starwindsoftware:sunil-pc-racnode1-lun-2-part1 -> ../../sdd1
lrwxrwxrwx 1 root root  9 Jul 13 16:51 pci-0000:00:07.1-ide-0:0 -> ../../hdc
lrwxrwxrwx 1 root root  9 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0 -> ../../sda
lrwxrwxrwx 1 root root 10 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 Jul 13 16:51 pci-0000:00:10.0-scsi-0:0:0:0-part2 -> ../../sda2
lrwxrwxrwx 1 root root  9 Jul 13 20:28 pci-0000:00:10.0-scsi-0:0:1:0 -> ../../sde

[root@racnode2 /]# ll /dev/disk/by-path/