Flexible Power Solutions from Starline

I came across this interesting flexible power solution from Starline - Busline Power Distribution. The track busway allows different types of customised power supplies and components to be planted on the track and it can be tapped instantly at any location along the track. It is interesting to know that we can put 3-phase and single-phase along the same track.

Do look at

1. Starline Videos 
2. Literature

Very need solution for flexible power deployment for DC.

Qsub and Interactive X Windows on CentOS

If you are using torque as a submission agent and wish to use interactive windows for your allocated node. You can use

Step 1:
Launch vncserver on the head node. For more information how to Using VNC Server on CentOS with Windows VNC Viewer

Step 2: Make sure you have configure the server allow ssh forwarding. At /etc/ssh/sshd_config

...
X11Forwarding yes
X11UseLocalhost yes
...

Restart the sshd services.

# service sshd restart

Step 3: Use the qsub command to launch interactive and. The "-X"

$ qsub -q myqueue -l nodes=1:ppn=8 -I -X

Total Reconfiguration of GPFS from scratch again

If you have messed things up in the configuration and wish to redo the entire setup again, you have to do the following. From our training at GPFS, there are 2 advisable ways. The first one is the recommended way. The latter one is the “nuclear” option.

For more information, see  Total Reconfiguration of GPFS from scratch again

Using Chage to manage password expiration and aging

As administrators, tools like chage to help manage the /etc/shadow information. /etc/shadow contains information such as

myuseid:$xxxxxxxxxeeerrrrr:15607:0:900:10:0::

Column	Description
1	UserID
2	Encrypted Password
3	Set the number of days since January 1st, 1970 when the password was last changed.
4	Minimum number of days between password changes to MIN_DAYS
5	Maximum number of days during which a password is valid
6	Set the number of days of warning before a password change is required
7	Set the number of days of inactivity after a password has expired before the account is locked
8	Set the date or number of days since January 1, 1970 on which the userid account will no longer be accessible. The date may also be expressed in the format YYYY-MM-DD

Best if you can use the command chage. For example, you can use the command

1. Listing of  password details

# chage --list  username

Last password change                                    : Feb 03, 2012
Password expires                                        : Jul 22, 2013
Password inactive                                       : Jul 22, 2013
Account expires                                         : never
Minimum number of days between password change          : 0
Maximum number of days between password change          : 60
Number of days of warning before password expires       : 10

2. Disable password aging for an user account

# chage -m 0 -M 99999 -I -1 -E -1 username

-m 0 (Min number of  days between password change to 0)
-M 99999 (Max Number of days between password change to 99999)
-I -1 (Set "Password Inactive" to never)
-E -1 (Set "Account expires" to never)

Last password change                                    : Feb 03, 2012
Password expires                                        : never
Password inactive                                       : never
Account expires                                         : never
Minimum number of days between password change          : 0
Maximum number of days between password change          : 99999
Number of days of warning before password expires       : 10

For more complete information, see

1.  6.6. Linux Password & Shadow File Formats
2. 7 Examples to Manage Linux Password Expiration and Aging Using chage

Basic Installation and Configuration of GPFS

I have written a few short basic tutorials on Installing and Configuring of IBM General Parallel File System (GPFS)

1. Basic Installing and Configuring of GPFS Cluster (Part 1)
2. Basic Installing and Configuring of GPFS Cluster (Part 2)
3. Basic Installing and Configuring of GPFS Cluster (Part 3)
4. Basic Installing and Configuring of GPFS Cluster (Part 4)

 Happy reading.

Singapore Inforcomm Resource Marketplace

Some information on Singapore Cloud Initiatives

Cloud Computing initiatives and policy directions in Asia during CloudAsia 2012 by Assistant CEO of iDA

Sharing on Cloud Computing experience by Mr Loo Kian Wai of Diners World Travel during the Singapore Cloud Forum seminar on 27 July 2012.

To view the videos,

Resolving error libthread-2.0.so.0 on Schrodinger

While executing maestro Schrodinger on CentOS 6, I encountered the following error

/usr/local/schrodinger/maestro-v90211/bin/Linux-x86/maestro: error while loading shared libraries: libgthread-2.0.so.0: cannot open shared object file: No such file or directory
Maestro: Could not load shared library

You have to install glib2 libraries first

# yum install glib2

Dependencies Resolved

===============================================================================================
 Package                 Arch               Version                     Repository        Size
===============================================================================================

Updating:
 glib2                   x86_64             2.22.5-7.el6                base             1.1 M

Updating for dependencies:
 glib2-devel             x86_64             2.22.5-7.el6                base             1.3 M

Transaction Summary
===============================================================================================
Upgrade       2 Package(s)

Total download size: 2.4 M
Is this ok [y/N]: Y

Now install libgthread-2.0.so.0 and its dependencies

# yum install libgthread-2.0.so.0

Dependencies Resolved

===============================================================================================
 Package             Arch               Version                       Repository          Size
===============================================================================================

Installing:
 glib2               i686               2.22.5-7.el6                  base               1.1 M
Installing for dependencies:
 gamin               i686               0.1.10-9.el6                  base               120 k

Transaction Summary
===============================================================================================
Install       2 Package(s)

Total download size: 1.2 M
Installed size: 5.4 M
Is this ok [y/N]: N
Exiting on user Command 

Udev Rules Documention

Taken from the documentation Writing udev rules

Udev is targetted to provide a userspace for a dynamic /dev directory with persistent device naming. If  you need to lock down your device naming, do take a look at this good writeup

Unable to open /dev/sdb with fdisk

Fdisk is a menu driven program for creation and manipulation of partition tables. The device is usually something like /dev/sda, /dev/sdb. A device name refers to the entire disks. /dev/sd? is the partition of the device. For example, /dev/sda1 refers to the first partition of the first device.

If you issued a command and you receive a corresponding message "unable to open /dev/sdb"

# fdisk /dev/sdb

Unable to open /dev/sdb

Linux is unable to locate or find the partition. One method to verify that it is so, do a listing of the
devices fdisk can see. In this example below, the partition has been created already.

# fdisk -l

Disk /dev/sdb: 2997.4 GB, 2997426536960 bytes
255 heads, 63 sectors/track, 364416 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1      267349  2147480811   83  Linux

WARNING: The size of this disk is 3.0 TB (2997400633344 bytes).
DOS partition table format can not be used on drives for volumes
larger than 2.2 TB (2199023255040 bytes). Use parted(1) and GUID
partition table format (GPT).

Once you have verified the presence of the device, do a fdisk /dev/sdb again

Adding time for dd to test and analyse read and write performance

This is an extension of a previous blog entry Using dd to test and analyse read and write performance. If you add time to dd

# time dd if=/dev/zero of=/home/myaccount/outfile bs=4M count=4096

4096+0 records in
4096+0 records out
17179869184 bytes (17 GB) copied, 136.832 seconds, 126 MB/s
real    2m16.834s
user    0m0.017s
sys     0m12.670s

Patch Release by Oracle for Zero day Vulnerability Alert

Oracle had posted the update release information on the link below:

1. Update release notes  - http://www.oracle.com/technetwork/java/javase/7u7-relnotes-1835816.html
2. Description of alert (Oracle Security Alert for CVE-2012-4681) and patch information - http://www.oracle.com/technetwork/topics/security/alert-cve-2012-4681-1835715.html

For more information:

1. The Advisory for Security Alert CVE-2012-4681 is located at http://www.oracle.com/technetwork/topics/security/alert-cve-2012-4681-1835715.html
2. Users can verify that they’re running the most recent version of Java by visiting: http://java.com/en/download/installed.jsp 
3. Instructions on removing older (and less secure) versions of Java can be found at http://java.com/en/download/faq/remove_olderversions.xml 

Adding new LUN dynamically in CentOS

After adding the new LUN(s) from SAN to CentOS Linux,

Step 1: Run the the command “rescan-scsi-bus.sh” , to dynamically detect and activate the new LUN. To understand this utility "rescan-scsi-bus.sh, see Scanning for SCSI new devices dynamically on CentOS

# /usr/bin/rescan-scsi-bus.sh -l

Host adapter 0 (aacraid) found.
Host adapter 1 (ata_piix) found.
Host adapter 2 (ata_piix) found.
Host adapter 3 (qla2xxx) found.
Host adapter 4 (qla2xxx) found.
Scanning SCSI subsystem for new devices
Scanning host 0 for  SCSI target IDs  0 1 2 3 4 5 6 7, LUNs Scanning 
0 1 2 3 4 5 6 7
Scanning for device 0 0 0 0 ...
OLD: Host: scsi0 Channel: 00 Id: 00 Lun: 00
      Vendor: ServeRA  Model: A                Rev: V1.0 
      Type:   Direct-Access                    ANSI SCSI revision: 02
Scanning for device 0 1 0 0 ...
OLD: Host: scsi0 Channel: 01 Id: 00 Lun: 00
      Vendor: IBM-ESXS Model: VPA146C3-ETS10 N Rev: A650
      Type:   Direct-Access                    ANSI SCSI revision: 05
.....
.....
..... 
0 new device(s) found.
0 device(s) removed.

Since LUN are not physical disk, there may not be "new devices" detected, but look at the middle of the information "Scanning host 0 for  SCSI target IDs  0 1 2 3 4 5 6 7, LUNs  0 1 2 3 4 5 6 7"


Step 2: Verify the LUN has been added. You the command lsscsi. If you do not have the utility, do a yum install

# yum install lsscsi

# lsscsi

..... 
.....
[3:0:0:0]    disk    IBM      1814      FAStT  0916  /dev/sdb
[3:0:0:1]    disk    IBM      1814      FAStT  0916  /dev/sdc
[3:0:0:2]    disk    IBM      1814      FAStT  0916  /dev/sdd
[3:0:0:3]    disk    IBM      1814      FAStT  0916  /dev/sde
[3:0:0:4]    disk    IBM      1814      FAStT  0916  /dev/sdf
[3:0:0:5]    disk    IBM      1814      FAStT  0916  /dev/sdg
[3:0:0:6]    disk    IBM      1814      FAStT  0916  /dev/sdn
.....
.....

Alternatively, you can use the command fdisk -l to check whether your LUN is represented in the /dev directory like /dev/sd*

# fdisk -l

.....
.....
Disk /dev/sdr: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdr1               1       65270   524281243+  83  Linux

Disk /dev/sds: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sds1               1       65270   524281243+  83  Linux

Scanning for SCSI new devices dynamically on CentOS

sg3_utils is a package of utilities for sending SCSI commands. For this particular blog entry, we will focus on the scanning for new SCSI new scsi dynamically without booting. Do

# yum install sg3_utils

==============================================================================
 Package                          Arch                     Version                       Repository              Size
==============================================================================
Installing:
 sg3_utils                        x86_64                   1.25-5.el5                    base                   501 k
Installing for dependencies:
 sg3_utils-libs                   x86_64                   1.25-5.el5                    base                    51 k

Transaction Summary
==============================================================================
Install      2 Package(s)
Update       0 Package(s)
Remove       0 Package(s)

Total download size: 553 k
Is this ok [y/N]:

To scan the SCSI-Bus. use the command

# rescan-scsi-bus.sh

Host adapter 0 (aacraid) found.
Host adapter 1 (ata_piix) found.
Host adapter 2 (ata_piix) found.
Host adapter 3 (qla2xxx) found.
Host adapter 4 (qla2xxx) found.
Scanning SCSI subsystem for new devices
Scanning host 0 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
Scanning for device 0 0 0 0 ...
OLD: Host: scsi0 Channel: 00 Id: 00 Lun: 00
      Vendor: ServeRA  Model: A                Rev: V1.0 
      Type:   Direct-Access                    ANSI SCSI revision: 02
Scanning for device 0 1 0 0 ...
OLD: Host: scsi0 Channel: 01 Id: 00 Lun: 00
      Vendor: IBM-ESXS Model: VPA146C3-ETS10 N Rev: A650
      Type:   Direct-Access                    ANSI SCSI revision: 05
.....
.....
.....
0 new device(s) found.
0 device(s) removed.

Green Revolution cooling announces full factory warranty from supermicro

According to the website announcement,  

Super Micro Computer, Inc. (Supermicro®) is now providing full warranty coverage for servers installed in the CarnotJet™ submersion cooling system. The assurance is a momentous step forward for Green Revolution Cooling and confirms the long-term reliability of servers installed in the CarnotJet™ system.

The warranty will cover motherboards, backplanes, add-on cards, power supplies, and processors for parts and labor. DIMM modules and SSDs are also covered in the warranty, as are all other manufacturer defects discovered during server operation in the CarnotJet™ system.

Lastly, Supermicro® is also offering a line of products available submersion-ready direct from the factory. With Supermicro® servers turn-key and fully guaranteed, it has never been easier to outfit your data center with submersion cooling from Green Revolution Cooling.

For more information of the announcement, do read Green Revolution Cooling Announces Full Factory Warranty from Supermicro®

Restoring a snapshot from Netapp from a newbie

I am a newbie to NetApp Storage solution. Creation and restoring Snapshot in Netapp could not be easier.

Basically, NetApp provides a very easy-to-recognise snapshot features. The Snapshot schedules are

1.  Weekly Snapshot copies are taken at 24:00 on Sunday, creating Snapshot copies called weekly.n, where n is an integer (weekly.0, weekly.1, weekly.2, and so on).
2. Nightly Snapshot copies are taken at 24:00 Monday through Saturday, creating Snapshot copies called nightly.n, where n is an integer (nightly.0, nightly.1, and so on).
3. Four hourly Snapshot copies are taken at 8 a.m., noon, 4 p.m., and 8 p.m., unless specified otherwise using the hourly Snapshot copy schedule in this window, creating Snapshot copies called hourly.n, where n is an integer (hourly.0, hourly.1, hourly.2, and so on).

You can easily select your snapshot schedule with some simple select and click.

If you make your snapshot directory visible, The snapshot content can be easily be seen from .shapshot directory of the NetApp volume.Restoration is very easy then. Assuming the NetApp volume is mounted as /home and you wish to recover nightly.0

# cp -avp /home/.snapshot/nightly.0/home/mysite/recover_my_folder /home/mysite/

that's it! I was quite amazed at the ease of the restoration of the lost folder.