Resizing a GPT partition with a ext4 filesystem [CentOS / RedHat]

1. Run parted on your device: parted /dev/sdX

2. Change display unit to sectors: unit s

3. Print current partition table and note the start sector for your partition: p

4. Delete your partition (won't delete the data or filesystem): rm <number>

5. Recreate the partition with the starting sector from above: mkpart primary <start> <end>

6. Exit parted: quit

7. Check the filesystem: sudo e2fsck -f /dev/sdXX

8. Resize filesystem: sudo resize2fs /dev/sdXX

Creating a Partition Size Larger Than 2TB [CentOS / RedHat]

You cannot create a Linux partition larger than 2 TB using the fdisk command. The fdisk won't create partitions larger than 2 TB. 

Here is an example how to create partition with 3.21 TB size:

1. fdisk -l /dev/sdb

2. parted /dev/sdb

3. (parted) mklabel gpt

4. (parted) unit TB

5. (parted) mkpart primary 0.00TB 3.21TB

6. (parted) print

7. mkfs.ext4 /dev/sdb1

8. # mkdir /data

   # mount /dev/sdb1 /data

   # df -H

Reset Root Password in Ubuntu

To enable the root account and reset the password type:

sudo passwd -u root

Create bootable Live USB - unetbootin

Introduction

UNetbootin allows you to create bootable Live USB drives for Ubuntu, Fedora, and other Linux distributions without burning a CD. It runs on Windows, Linux, and Mac OS X. You can either let UNetbootin download one of the many distributions supported out-of-the-box for you, or supply your own Linux .iso file if you've already downloaded one or your preferred distribution isn't on the list.

Requirements

• Microsoft Windows 2000/XP/Vista/7, or Linux, or Mac OS X 10.5+. Note that resulting USB drives are bootable only on PCs (not on Macs).
• Internet access for downloading a distro to install, or a pre-downloaded ISO file

Features

UNetbootin can create a bootable Live USB drive, or it can make a "frugal install" on your local hard disk if you don't have a USB drive. It loads distributions either by downloading a ISO (CD image) files for you, or by using an ISO file you've already downloaded. 

Download: http://unetbootin.sourceforge.net

How to Login as Root in Ubuntu

1. sudo passwd root

2. sudo sh -c 'echo "greeter-show-manual-login=true" >> /etc/lightdm/lightdm.conf.d/50-unity-greeter.conf' 

3. reboot the system

Install Adobe Flash Player on Ubuntu

1. Open a terminal window

2. Type in the following commands then hit Enter after each.

sudo apt-get update

sudo apt-get install flashplugin-installer

Troubleshooting the vCenter Server Appliance with Single Sign-On login

Details

The two most common network-related problems when connecting to a vSphere Server Appliance using the Web Client and Single Sign-On (SSO) are SSL certificate failure and a changed SSO server IP address. These errors are seen when the problem is encountered:

• Failed to connect to VMware Lookup Service https://<vCVA IP address>:7444/lookupservice/sdk - SSL certificate verification failed. 
• Failed to communicate with the vCenter Single Sign On server https://<vCVA IP address>:7444/ims/STSService.

Solution

If the SSO SSL certificate failed, the network identification for the vSphere Server Appliance has changed, but the SSO SSL certificate has not been updated to match it. For instructions on changing the certificate, see the technical note Replacing Default vCenter 5.1 and ESXi Certificates. 

To resolve this issue, toggle the certificate settings:

1. Log in the vCenter Server Appliance Web interface at https://hostname:5480/.
2. Click the Admin tab.
3. Regenerate certificates by selecting Toggle certificate setting. The Certificate regeneration enabled option under the Administration settings displays Yes.
4. Reboot the vCenter Server Appliance.

Notes: 

• vCenter Server generates new default certificates using this option. For systems that use custom certificates, you must regenerate the certificates manually.
• Regeneration of default certificates may take a long time to complete. For more information, see Rebooting vCenter Server Appliance 5.1 takes a long time when regenerating SSL certificates (2058332).

Deleting Temporary User Profile on Windows Server 2008 R2

If every times you are logging as temporary user to Windows Server 2008 R2, you can do a registry trick to solve this problem. Run regedit.exe and navigate here:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

You should see two entry as and .bak. Also check their home folder paths. If you are sure that .bak is your real profile, just delete the and rename .bak as . Then logoff. The next new logon will be your real desktop profile.

You get the error "squid Unable to determine IP address from host name

Synopsis

You get the error "squid Unable to determine IP address from host name for XXXXXX" in your web browser when trying to access a site

Article

This usually occurs if you are attempting to access an internal site, such as http://intranet If fo.r any reason squid is unable to resolve "intranet" to an IP address using the name servers provided it will display this error message.

To fix this, you should add an entry to the /etc/hosts file on your CensorNet server. To do this :-

1. Log in as root

2. Type:

nano /etc/hosts

3. On a new line, add:-

10.0.0.25    intranet

(replace with the correct hostname and IP)

4. Press CTRL+X then press Y followed by enter.

5. Restart squid

/etc/init.d/squid restart

Try the web site again and the problem should be solved.

Link:

http://www.censornet.com/en/kb/you_get_the_error_squid_unable_to_determine_ip_address_from_host_name/

Juniper - Backup and Restore Configuration by using ftp

** You can use FileZilla FTP Server

Source:

ftp <ip>

ftp> bin

ftp> lcd /config
ftp> put juniper.conf.gz




Destination:
1. root@%
      cli

2. root>
    configure

3. load update terminal
4. CTRL + D
5. commit

Unknown OS character set 'cp862 and Switching to the default character set 'latin1' in mySQL

If you are trying to run some sql  text file in mysql and get an error like this:

C:\wamp\bin\mysql\mysql5.6.12\bin\mysql.exe: Unknown OS character set 'cp862'.

C:\wamp\bin\mysql\mysql5.6.12\bin\mysql.exe: Switching to the default character set 'latin1'.

You get the error because the engine is use the default. To set the default to UTF-8 in "my.ini" file you have to add this lines:

[client]
default-character-set=utf8

[mysql]
default-character-set=utf8


[mysqld]
collation-server = utf8_unicode_ci
init-connect='SET NAMES utf8'
character-set-server = utf8

save the file and restart the service.

NexentaStore installation on vSphere

Short how-to on installing NexentaStore 3.3.x or 4.0 on vSphere 5.x including vmware-tools.

NexentaStor community v4 is a OpenIndiana based ZFS storage appliance.  Out of the box it is limited to 18TB of raw disk storage in the free version.

This howto supplements the installations instructions on creating a VMware vSphere guest.

This install will use a e1000 nic for managment traffic, and a 2nd vmxnet3 NIC configured with Jumbo frames for storage traffic.

Ideally a second SAS controller should be passed-through directly (directpath I/O) to the VM for your storage disks,  but this requires VT-d support in the BIOS and this is not available on my Dell 2950 servers. 

Preperation

1. Download ISO v4 (beta) image from Nexenta
2. Upload ISO to your ISO (NFS) share in your vSphere environment.

Installation

1. Create a new VM with OS type ( Solaris 10 ) ,  2vcpu, 4GB RAM, and a 10 GB thick disk.
   Use a single e1000 NIC.
   Note: as of 3.1.3.5, select PVSCSI disk controller prior to install.
2. Attach NexentaStore ISO to CD, mounted on boot.
3. Power on VM,  and run installer.  You will get a device ID, that must be entered into the registration page at http://www.nexenta.com/register-eval,  and it will email you the community (free) license code.
4. Setup the networking to use a static IP in the installer.
5. Select web page to use HTTPS,  and port 2000,   set both web and root
   Passwords.
6. Reboot and verify web access and password work.

VMware Tools

1. Unmount existing installer CDROM, and select do not mount at power-on.
2. Reboot VM.     When up select "Install Vmware-tools"
3. Login to VM as root.  ( Note when logging in as root you get the "NMC" management prompt.  This is a restricted CLI,  and is not BASH )
4. To get a bash prompt type
   

   option expert_mode=1
   !bash

5. The CD should have auto-mounted as /media/VMware\tools      Verify with Mount command.    Copy the Tools installer to /root and untar.
   

   cd /media/VMware\ Tools
   cp vnmware-solaris-tools.tar.gz /root
   cd /root
   tar -xzf vmware-solaris-tools
   cd vmware-tools-distrib

6. Run the installer.
   

   ./vmware-install.pl

7. Use defaults.  When you get to the step where you "configure" VMware tools answer NO
8. Run the configure (defaults) option.
   

   vmware-config-tools.pl -d

9. This step might fail with a note that "SUNWuiu8" package is required.
   Edit the vmware-config-tools.pl script to comment out this section.
   

   cd /usr/bin
   vi vmware-config-tools.pl
   /SUNWuiu          (search for WUNWuiu string )

10. When the code is found insert "#" comment characters in front of the entire IF statement
    

      # Be sure that the SUNWuiu8 package is installed before trying to configure
      #  if (vmware_product() eq 'tools-for-solaris') {
      #      if(does_solaris_package_exist('SUNWuiu8') == 0){
      #         error("Package \"SUNWuiu8\" not found. " .
      #           "This pac kage must be installed in order " .
      #           "for configuration to continue." . "\n\n") ;
      #       }
      #  }

11. Save file with ":"  then wq.
12. Re-run configuration with defauts.
    

    vmware-config-tools.pl -d

13. The configuration should succeed this time.   After it finishes, reboot.
    

    exit                ( exit bash back to NMC)
    setup appliance reboot
    
    Note that the vmxnet3 NIC is now recognized after vmware-tools is installed.

14. Shutdown VM,  and install a vmxnet3 NIC,  power up VM, and use GUI to configure NIC for storage network.   Static IP,   MTU=9000  ( Skip MTU, broken, see below )
15. Reboot Appliance so that MTU takes effect.

VMXNET3  Note: in v 3.1.3.5 vmxnet3 did  not seem to work so I reverted to e1000.  In v4 beta (As of 5/25/13 )  vmxnet3 works but setting the MTU is broken, even from bash. See this link for low level commands to set MTU.

Add storage disks

My setup does not support DirectPath IO to my hosts SAS storage,  so we will have to use VMFS volumes.    This is not ideal, as ZFS hot-swap doesn't work and you will likely have to do a shutdown and manually replace any failed disks.

We will create a VMFS-5 volume filling up the entire disk for each disk dedicated to storage.  In my example my host has 6 2TB SAS drives.

Note the OS and all storage disks must be on the same host,  and the VM disabled for vMotion.

1. On host with storage,  create VMFS-5 partitions filling the entire disk, for each one of the storage disks.
2. In NexentaStor create one new disk that is the maximum size for each VMFS volume.  Set this disk options to Thick, lazy-zero.   Set Disk-Mode = Independent (Persistent )
   Important:  Verify disk mode to make sure disk except OS are set as above.  This is to make sure that VMware snapshots do not affect the NexentaStor disks.
3. Power on Nexenta and make sure disks show up under "Settings, Disks"

ZFS notes

ZFS uses slightly different terminology than traditional volume managers

In ZFS a zPool is composed of vDev's ( each of which is redundant set or mirror )

zPool (many vDev's) ->  vDev (several disks)

Folder ( quota allocated within zPool )

Howerver in NexentaStor these items are  often referred by their non-ZFS terms.

• Volume ->  this is really a zPool
• Share   ->   this is a ZFS folder  ( with quota )
• zVol     ->    this is a ZFS volume ( block device for iSCSI )

NFS Setup

The NFS protocol is recommended over iSCSI.   The storage allocated to each 'share' is then really only a quota,  and you can change it at will.

Set NFS server as follows for ESXi compatability:

Data management, Shares, NFS Server, Configure:

Set "Client Version" = 3

Create Volume ( zPool )

Create a single z-pool called "tank"   ( this is a play on the term pool ... )

Create Folder ( share )

NOTE:  Recommend not using de-duplication on any volume as it may be difficult to turn off without issues.  ( This was as of v3.3.x ,  status in v4 unknown )

Each folder has options ( compress,  block-size, etc. ) These are typically used for NFS, or CIFS mounts.   You can set/change the quote on each folder while running.  To create a NFS mount for ESXi hosts.

1. Data Management, Share, Create
2. Don't change de-dup.  For VM's use 128K blocks, bias=latency.   Create Folder
3. Enable NFS sharing on folder.
4. Edit NFS options, leave defaults, Anon=Y, AnonRW=Y
   Set Read/Write to @10.25.1.0/24  ( to allow 10.25.1.x hosts write access )

Thanks to lmarzke from: http://plone.4aero.com/Members/lmarzke/howto/nexentastore-installation-on-vsphere

CentOS / Ubuntu Time Zone issue resolve

To know when your clock is going to change:

zdump -v /etc/localtime | grep 2013

To install the update Time zone:

yum install tzdata

TUI to configure zone:

tzselect

Importent Path to know:

/usr/share/zoneinfo

/etc/sysconfig/clock

/etc/localtime

**Fix to Ubuntu in old version:

#Ubuntu has an open bug:

#https://bugs.launchpad.net/ubuntu/+source/tzdata/+bug/1158834

#Until fixed:

#Check if the settings are right:

zdump -v /etc/localtime | grep 2013

#If wrong:

mkdir $HOME/dstfix2013

cd $HOME/dstfix2013

wget -N ftp://ftp.iana.org/tz/data/asia

sudo zic asia

sudo ln -sf /usr/share/zoneinfo/Asia/Jerusalem /usr/share/zoneinfo/Asia/Tel_Aviv

# reconfigure the system to use the new zone files

sudo dpkg-reconfigure tzdata

# Check again

zdump -v /etc/localtime | grep 2013

How to generate CPU load?

http://unixadministrator.blogspot.co.il/2008/01/how-to-generate-cpu-load.html

Sometimes, system administrators are asked to generate 'dummy' load on CPU to test the load vs performance. Here is a short example which shows how to generate load per CPU or per Core basis (actually threads):

 # perl -e 'while (--$ARGV[0] and fork) {}; while () {}' 4

The last digit "4" in this case indicates how many CPUs or threads or cores you want to load by this method. This indeed is a good idea to test the CPU performance when some of the threaded/virtual CPUs are loaded.

When I gave the above command, in other terminal window for same server, I can observe something like this:

# mpstat 5
CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
  0    0   0   10   213  105   17    0    0    0    0    38    0   2   0  98
  1    0   0    0     1    0    0    0    0    0    0     0    0   0   0 100
  2    0   0    0     2    0    2    0    0    0    0     0    0   0   0 100
  3    0   0    0     1    0    0    0    0    0    0     0    0   0   0 100
  4    0   0    0     2    0    2    0    0    0    0     5    0   0   0 100
  5    0   0    3     4    0    6    0    0    0    0     0    0   0   0 100
  6    0   0    1    13    6   11    0    0    0    0     0    0   0   0 100
  7    0   0    4     3    0    4    0    0    0    0    10    0   0   0 100
CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
  0   21   7  139   227  118   18    9    0    1    0    53   85   1   0  14
  1    4   0    7     9    0   16    0    4    0    0     4    1   1   0  98
  2   10   0    0     8    0    5    5    0    1    0     1   85   0   0  15
  3    0   1   34     7    0   11    0    1    0    0     3    0   0   0 100
  4    6   0    0     6    0    2    4    0    0    0     4   84   0   0  16
  5    7   0    0     2    0    1    0    1    1    0     1    0   0   0 100
  6   10   0    4    12    5    3    5    0    0    0     1   85   0   0  15
  7    0   0   21    16    0   31    0    0    0    0    10    0   0   0 100
CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
  0    0   0   30   207  106    0    8    0    0    0     0  100   0   0   0
  1    0   0    0     9    0   15    0    1    0    0    23    0   1   0  99
  2    0   0    0     6    0    0    5    0    0    0     0  100   0   0   0
  3    0   0    3     8    0   13    0    1    0    0    12    0   0   0 100
  4    0   0    0     6    0    0    5    0    0    0     0  100   0   0   0
  5    0   0    0     2    0    0    0    0    0    0     0    0   0   0 100
  6    0   0    1    10    3    2    7    0    0    0     0  100   0   0   0
  7    0   0    0     1    0    0    0    0    0    0     0    0   0   0 100
^C

The 'top' command output in this case will look like following:

# top
last pid:   698;  load avg:  1.61,  0.44,  0.19;       up 25+19:31:24                                                                             10:59:01
34 processes: 29 sleeping, 5 on cpu
CPU states: 49.8% idle, 50.0% user,  0.2% kernel,  0.0% iowait,  0.0% swap
Memory: 8192M phys mem, 6680M free mem, 4099M total swap, 4099M free swap

   PID USERNAME LWP PRI NICE  SIZE   RES STATE    TIME    CPU COMMAND
   694 root       1   0    0 6368K 3256K cpu/0    0:35 12.50% perl
   696 root       1   0    0 6360K 1672K cpu/7    0:35 12.45% perl
   697 root       1   0    0 6360K 1672K cpu/1    0:35 12.45% perl
   695 root       1   0    0 6360K 1800K cpu/6    0:35 12.14% perl
   698 root       1  59    0 2944K 2104K cpu/3    0:00  0.03% top
   679 root       1  59    0   10M 3576K sleep    0:00  0.00% sshd
   119 root      24  59    0 4576K 4232K sleep    1:25  0.00% nscd
     9 root      15  59    0   10M 9704K sleep    0:42  0.00% svc.configd
   238 root       4  59    0 7888K 4664K sleep    0:29  0.00% inetd
     7 root      12  59    0   13M 9904K sleep    0:34  0.00% svc.startd
   302 root      16  59    0   15M 9400K sleep    0:27  0.00% fmd
   202 root       1  59    0 1360K 1176K sleep    0:04  0.00% utmpd
   183 daemon     1  59    0 2848K 2360K sleep    0:11  0.00% rpcbind
   253 root       3  59    0 7464K 3160K sleep    0:08  0.00% automountd
     1 root       1  59    0 2512K 1920K sleep    0:05  0.00% init

Postfix: fatal: parameter inet_interfaces [solved]

Postfix: fatal: parameter inet_interfaces: no local interface found for IP

Edit the file /etc/postfix/main.cf (sudo nano /etc/postfix/main.cf), search for the line:

inet_interfaces = all

And change it to:

inet_interfaces = 127.0.0.1, 66.66.66.66, 66.66.66.67

Save, exit and restart postfix (sudo service postfix restart).

Zabbix configuration

1. Install Zabbix Agent on Cent-OS 6.X

cd /etc/yum.repos.d/ ; wget "http://download.opensuse.org/repositories/home:/ericgearhart:/zabbix/CentOS_CentOS-6/home:ericgearhart:zabbix.repo"
yum install zabbix-agent -y
chkconfig --add zabbix-agentd
chkconfig zabbix-agentd on
vi /usr/local/etc/zabbix_agentd.conf
service zabbix-agentd start

* Update CLI - Install Zabbix Agent:

# rpm -ivh http://repo.zabbix.com/zabbix/2.2/rhel/6/x86_64/zabbix-release-2.2-1.el6.noarch.rpm
# yum install zabbix-agent
# chkconfig zabbix-agent on
# vi /etc/zabbix/zabbix_agentd.conf
# /etc/init.d/zabbix-agent start

* MySQL Monitor:

  http://vmhacks.com/how-to-setup-mysql-enterprise-monitoring-with-zabbix/

• [root@vmhacks.com ~]# mkdir /var/lib/zabbix
• Right, now you can place your MySQL client connection information into this directory.  When the Zabbix agent runs the UserParameter commands, it will check the /var/lib/zabbix/.my.cnf  for a username and password.  So that means you need something like the following in your /var/lib/zabbix/.my.cnf file:
• [client]
• user=zabbix_boy
• password=boyimtired

  http://blog.themilkyway.org/2013/11/how-to-monitor-mysql-using-the-new-zabbix-template-app-mysql/

# mysql -uroot -p<mysql root password goes here> -e"GRANT USAGE ON *.* TO 'zabbix'@'127.0.0.1' IDENTIFIED BY '123456'";

# mysql -uroot -p<mysql root password goes here> -e"GRANT USAGE ON *.* TO 'zabbix'@'localhost' IDENTIFIED BY '123456'";

# mysql -uroot -p<mysql root password goes here> -e"flush privileges"

# mysql -uzabbix -p123456 -e"status"

Create a new /etc/zabbix/.my.cnf config file with the mysql login (created above) to be used by zabbix to connect to the mysql server for monitoring purpose.

1 2 3 4 5 6

[mysql] user=zabbix password=123456 [mysqladmin] user=zabbix password=123456

Your zabbix agent config file should already have the line "Include=/etc/zabbix/zabbix_agentd.d/" which will automatically load all config files under that folder by default (including theuserparameter_mysql.conf file). If not then you will need to do the below to load the config file.

In the main zabbix config file include the below line to enable loading of the mysql file.

Include=/etc/zabbix/zabbix_agentd.d/

Restart the zabbix agent to load the new config file.

service zabbix-agent restart

2.Set time and date on Zabbix server in the BIOS and on the OS with the command:

date MMDDhhmmYYYY

OR use "yast"

3. How to set "date.timezone" option in php.ini - Change the date.timezone value in PHP:

#vi /etc/php5/apache2/php.ini

find&change:  date.timezone = "Asia/Jerusalem"

#/etc/init.d/apache2 restart