Welcome to Blog,

This blog was created to share my experiences to help other people. On this page you can find an information about Linux/Unix (Redhat, HP-UX, OEL, Debian …etc.), backup, storage and troubleshooting topics.

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EXADATA: How to configure ssh for current user on a list of nodes?

APPLIES TO:

Oracle Exadata Storage Server Software – Version 11.2.1.2.0 and later.

GOAL

Customer needs steps to configure ssh on exadata.

SOLUTION

Run the following on a db node, and follow the prompts.
/opt/oracle.SupportTools/onecommand/setssh-Linux.sh -h /opt.oracle.SupportTools/onecommand/all_nodelist_group
This will configure passwordless ssh for current user for the list of nodes specified in all_nodelist_group.

 

If the utility is missing, it can be extracted from a current download of the onecommand utility

see Document : 888828.1 – Exadata Database Machine and Exadata Storage Server Supported Versions

 

/opt.oracle.SupportTools/onecommand/all_nodelist_group —you may need to create a file with the host entries for which you need SSH.

Example;

IBSWITCH_GROUP –Keep the ibswitches in that file and pass in that command.

[root@exa01dbadm01 ~]# cd /opt/oracle.SupportTools/onecommand/
[root@exa01dbadm01 onecommand]# vi IBSWITCH_GROUP
exa01sw-iba01
exa01sw-ibb01

[root@exa01dbadm01 onecommand]#chmod 775  IBSWITCH_GROUP 

[root@exa01dbadm01 onecommand]# ./setssh-Linux.sh -s -p  PassWord -n N -h IBSWITCH_GROUP
[root@exa01dbadm01 onecommand]# cat IBSWITCH_GROUP
exa01sw-iba01
exa01sw-ibb01
[root@exa01dbadm01 onecommand]# ssh exa01sw-iba01
Last login: Sat Oct 14 15:39:56 2017 from exa01dbadm01.omsan.com.tr
You are now logged in to the root shell.
It is recommended to use ILOM shell instead of root shell.
All usage should be restricted to documented commands and documented
config files.
To view the list of documented commands, use “help” at linux prompt.
[root@exa01sw-iba01 ~]#

For different user from root (for example oracle user)

EXADATA passwordless SSH login not working for oracle user

i. Login to the oracle account:
# su – oracle

ii. Create a dcli group file listing the nodes in the Oracle Cluster.

iii. Run the setup ssh script (this assumes the oracle password on all servers in the dbs_group list is set to “welcome””
$./setssh-Linux.sh -s -p welcome1 -n N -h dbs_group

Source:Oracle support note(Doc ID 1923785.1)

 

How can I check the port status of my fibre channel HBA?

Environment

  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 6

Issue

  • Need to check the port status of my fibre channel HBA

Resolution

  • The state of the port can be checked within the /sys/class directory either via
$ systool -c fc_host -v    from sysfsutils package
Class = "fc_host"

  Class Device = "host10"
  Class Device path = "/sys/class/fc_host/host10"
    fabric_name         = "0x200000e08b8068ae"
    issue_lip           = 
    node_name           = "0x200000e08b8068ae"
    port_id             = "0x000000"
    port_name           = "0x210000e08b8068ae"
    port_state          = "Linkdown"
    port_type           = "Unknown"
    speed               = "unknown"
    supported_classes   = "Class 3"
    supported_speeds    = "1 Gbit, 2 Gbit, 4 Gbit"
    symbolic_name       = "QLE2460 FW:v5.06.03 DVR:v8.03.07.15.05.09-k"
    system_hostname     = ""
    tgtid_bind_type     = "wwpn (World Wide Port Name)"
    uevent              = 

    Device = "host10"
    Device path = "/sys/devices/pci0000:00/0000:00:04.0/0000:08:00.0/host10"
      optrom_ctl          = 
      reset               = 
      uevent              = 
:

or if sysfsutils package is not installed

[root@axx /]# grep -v "zZzZ" -H /sys/class/fc_host/host*/port_state
/sys/class/fc_host/host0/port_state:Linkdown
/sys/class/fc_host/host1/port_state:Linkdown

 

Raid Card options: Write-through,write-back, write-around

Aim:Reducing latency in accessing data.

What is the difference between write-through, write-around, write-back?

Cache:Storing copy of data temporarily and local to CPU.

Write-through: is a storage method in which data is written in to the cache (RAM-Memory) and corrosponding main memory (disk-SAS/SATA etc.) location at same time. Select this option where data loss cannot be tolerated.

Advantages;

  • Minimize the risk of data loss.
  • safely.
  • Ensures that nothing will get lost if crash, power failure etc. low read latency.

Disadvantages;

  • Every write operation must be done twice and this redundancy takes a time.high write latency.

Write-back: is a storage method in which data is written in to the cache every time a change occurs but is written in to the disk(SAS/SATA etc.) only at specified intervals or under certain conditions.Select this option where data loss can be tolerated

Advantages:

  • Optimize system speed because it takes less time to write data into cache.

Disadvantages:

  • The risk of data loss in case of a crash or other adverse event.

Write-around: is a similar to write-through cache but write I/O is written directly to permanent storage (disks-SAS/SATA etc.) bypassing the cache.

How to setting cache setting on HP EVA storage?

From create virtual disk->Advance settings->Write cache policy:

raidcardoptions

 

Linux (CUPS) Spooler Troubleshooting

Step 1:Check Error logs

Command:    tail -f /var/log/cups/error_log 

I [08/Mar/2017:16:58:03 +0300] [Job ???] Request file type is text/plain.
 I [08/Mar/2017:16:58:03 +0300] [Job 7] Adding start banner page "none".
 I [08/Mar/2017:16:58:03 +0300] [Job 7] Adding end banner page "none".
 I [08/Mar/2017:16:58:03 +0300] [Job 7] File of type text/plain queued by "emdadm".
 I [08/Mar/2017:16:58:03 +0300] [Job 7] Queued on     
 "TEST_LABEL_PRINTER" by "emdadm".

Linux (CUPS) Spooler Commands

Step 2:To view the status of all print queues:

Command:    lpc status

Example:

serddad1:~ # lpc status
 TEST_LABEL_PRINTER:
 printer is on device 'socket' speed -1
 queuing is enabled
 printing is enabled
 1 entries
 daemon present

PROD_LABEL_PRINTER:
 printer is on device 'socket' speed -1
 queuing is enabled
 printing is enabled
 1 entries
 daemon present

Step 3:To check the status of a single print queue and view a list of pending jobs:

Command:  lpc status printer_name,  lpstat -P printer_Name,

lpstat -pprinter_name

Example:

serddad1:~ # lpc status TEST_LABEL_PRINTER
 TEST_LABEL_PRINTER:
 printer is on device 'socket' speed -1
 queuing is enabled
 printing is enabled
 1 entries
 daemon present
 serddad1:~ # lpstat -P TEST_LABEL_PRINTER
 TEST_LABEL_PRINTER-1 root 17408 Tue Feb 28 14:38:09 2017
 serddad1:~ # lpstat -pTEST_LABEL_PRINTER
 printer TEST_LABEL_PRINTER is idle. enabled since Thu Mar 9 14:30:20 2017

Step 4:To remove a single print job:

Command:  cancel printer_name-id(check output of lpstat -P TEST_LABEL_PRINTER)  ,

Example:

serddad1:~ # cancel TEST_LABEL_PRINTER-1

Step 5:To remove all print jobs in a queue:

Command: cancel -a  printer_name

Example:

serddad1:~ # cancel -a TEST_LABEL_PRINTER

Step 6:To enable  a queue:

Command:cupsenable  printer_name

Example:

serddad1:~ # cupsenable TEST_LABEL_PRINTER

Step 7:To disable  a queue:

Command:cupsdisable  printer_name

Example:

serddad1:~ # cupsdisable TEST_LABEL_PRINTER

Step 8:To enable all queues:

Command:

lpstat -p | grep disabled | awk '{print $2}' | xargs cupsenable

Example:

serddad1:~ #lpstat -p | grep disabled | awk '{print $2}' | xargs cupsenable

Step 9:To print a test job:

Command:

echo test_page | lpr -P printer_name

Example:

serddad1:~ #echo test_page | lpr -P  TEST_LABEL_PRINTER

Step 10:To restart/refresh the cups service:

Command:

service cups restart

ORA-15032, ORA-15040, ORA-15042 Error on Oracle ASM

ERROR:Try to mount the disk group on ASM

SQL> alter diskgroup RECOc1 mount;

alter diskgroup RECOc1 mount

*

ERROR at line 1:

ORA-15032: not all alterations performed

ORA-15040: diskgroup is incomplete

ORA-15042: ASM disk “2” is missing from group number “2”

Check  Alert Log:

Wed Feb 15 15:32:15 2017
NOTE: Disk RECOC1_0000 in mode 0x7f marked for de-assignment
NOTE: Disk RECOC1_0001 in mode 0x7f marked for de-assignment
ERROR: diskgroup RECOC1 was not mounted
ORA-15032: not all alterations performed
ORA-15040: diskgroup is incomplete
ORA-15042: ASM disk “2” is missing from group number “2”

 

SOLUTION:

All transactions must be done by root user.

1-Scan and find RECOC1 disks with scripts;

/etc/init.d/oracleasm querydisk -d `/etc/init.d/oracleasm listdisks -d` | \

cut -f2,10,11 -d” ” | \

perl -pe ‘s/”(.*)”.*\[(.*), *(.*)\]/$1 $2 $3/g;’ | \

while read v_asmdisk v_minor v_major

do

v_device=`ls -la /dev | grep ” $v_minor, *$v_major ” | awk ‘{print $10}’`

echo “ASM disk $v_asmdisk based on /dev/$v_device [$v_minor, $v_major]”

done

2-Remove RECOC* found disks

/etc/init.d/oracleasm deletedisk RECOC1

/etc/init.d/oracleasm deletedisk RECOC2

/etc/init.d/oracleasm deletedisk RECOC3

3-Add re-create RECOC* disks

oracleasm createdisk RECOC1 /dev/sdd1;

oracleasm createdisk RECOC2 /dev/sdh1;

oracleasm createdisk RECOC3 /dev/sdj1;

ora-15032

if flashback on, you have to off it on your oracle database and use the grid user for below processes.

  1. On GUI–>open asmca—>Disk Group Name:RECOC1  select 3  disks to add diskgroup
  2. check your alert log again.

SUCCESS: diskgroup RECOC1 was mounted
Wed Feb 15 15:46:30 2017
SUCCESS: CREATE DISKGROUP RECOC1 EXTERNAL REDUNDANCY DISK ‘/dev/oracleasm/disks/RECOC1’ SIZE 102398M ,
‘/dev/oracleasm/disks/RECOC2’ SIZE 1048570M ,
‘/dev/oracleasm/disks/RECOC3’ SIZE 511993M ATTRIBUTE ‘compatible.asm’=’12.1.0.0.0′,’au_size’=’1M’ /* ASMCA */
Wed Feb 15 15:46:30 2017

 

device ethX does not seem to be present, delaying initialization..

Problem :device ethX does not seem to be present, delaying initialization…

Solution: fix the problem by deleting the /etc/udev/rules.d/70-persistent-net.rules file and restarting server.

Step 1:Restart network daemon.

#Service network restart

Shutting down loopback interface:
Bringing up loopback interface:
Bringing up interface eth0: Device eth0 does not seem to be present, delaying initialization.

Step 2:

#rm -rf /etc/udev/rules.d/70-persistent-net.rules

Step 3:

#reboot

If your server is virtualbox;

Solution:

step 1:copy the mac address from the inside file “/etc/sysconfig/network-scripts/ifcfg-eth0” to the host to virtualbox–>Settings–>network–>Adapter 1–>advanced–>MAc address

step 2:

#service network reload

 

 

root user SSH Failed Login Attempts on Oracle Exadata

Problem:root user SSH Failed Login Attempts on Oracle Exadata

Solution: check log file and unlock user

[root@exa01dbadm01 ~]# tail -f /var/log/secure

Jan 20 08:12:02 exa01dbadm01 sshd[119402]: Failed password for root from 172.18.17.71 port 61446 ssh2

Jan 20 08:12:14 exa01dbadm01 sshd[119402]: pam_tally2(sshd:auth): user root (0) tally 23, deny 5

[root@exa01dbadm01 ~]# pam_tally2 –user=root

Login           Failures Latest failure     From

root               23    01/20/17 09:12:14 172.18.17.71

[root@exa01dbadm01 ~]# pam_tally2 –user=root –reset

Login           Failures Latest failure     From

root               23    01/20/17 09:12:14 172.18.17.71

[root@exa01dbadm01 ~]# pam_tally2 –user=root

Login           Failures Latest failure     From

root                0