iSCSI target feature has been available since s10u7. Here is some information for setting up a basic iSCSI target configuration. High level steps to follow are as shown below : create a base directory configure the backing store Creating a target Add ACL to target 1. create a base directory The base directory is used to store the iSCSI target configuration data, and needs to be defined prior to using the iSCSI target for the first time. You can create a base directory with the … [Read more...] about How to Configure iSCSI targets on Solaris 10
How to obtain virtual/physical CPU information in Oracle VM (XEN)
This post explains how to obtain virtual or physical CPU usage of an Oracle VM Server, including actual CPU usage and running time of guest domains. Guest-specific (Dom-U) CPU usage can be obtained by running commands on the guest itself, for example; top, ps, and sar. If, however, you wish to obtain specific CPU usage, including that of the Oracle VM Server management domain/hypervisor (Dom-0), the following xen-tools utilities are available to run on the Oracle VM … [Read more...] about How to obtain virtual/physical CPU information in Oracle VM (XEN)
iSCSI connection command examples (Cheat Sheet)
Internet Small Computer System Interface (iSCSI) is an Internet Protocol (IP)–based storage standard that connects iSCSI initiators to iSCSI targets over IP networks. To put it simply, the SCSI packets are encapsulated in IP packets and sent over a standard IP network, where the initiators and targets reassemble the packets and interpret the commands carried by these packets. iSCSI takes advantage of existing IP infrastructure, unlike Fibre Channel (FC), which requires special cables and … [Read more...] about iSCSI connection command examples (Cheat Sheet)
“iscsiadm” Discovery TimeOut With Two Or More Network Interfaces in CentOS/RHEL
The Problem iscsiadm discovery times out when both the interfaces are up, but it works fine with single interface up. # iscsiadm -m discovery -t st -p x.x.x.x iscsiadm: connect to x.x.x.x timed out iscsiadm: connect to x.x.x.x timed out The Solution This issue could occur when two or more Ethernet interfaces are connected to the same subnet or when iSCSI connection is configured to use any specific interface. In such cases when packets are delivered to the wrong interface then the OS … [Read more...] about “iscsiadm” Discovery TimeOut With Two Or More Network Interfaces in CentOS/RHEL
Unable To Extend LVM File System with Associated Snapshot in CentOS/RHEL
The Problem User is unable to Extend LVM file system which has snapshot, Error "Snapshot origin volumes can be resized only while inactive: try lvchange -an". The user has created a snapshot on non-root LVM volume as shown below. # lvcreate --size 100M --snapshot --name testsnap /dev/testVG/testLV Logical volume "testsnap" created # lvs -a -o+devices LV VG Attr LSize Origin Snap% Move Log Copy% Convert Devices LogVol00 VolGroup00 -wi-ao 7.91G … [Read more...] about Unable To Extend LVM File System with Associated Snapshot in CentOS/RHEL
Solaris Zone Install Fails With Cpio Error
The Problem Error when trying to install full root zone ERROR: cannot install zone: cannot access [/usr/bin/cpio] (exec failure) NOTE: Sparse root install was successful. The Solution 1. Check the permissions of the cpio executable on the problematic system first. # ls -al /usr/bin/cpio -rwxrwxrwx 1 root bin 85924 Sept 9 2018 /usr/bin/cpio Correct permissions should be: # ls -al /usr/bin/cpio -r-xr-xr-x 1 root bin 85856 Sept 9 2018 /usr/bin/cpio 2. Also many errors during … [Read more...] about Solaris Zone Install Fails With Cpio Error
RPM : package installation Error : cpio: read failed
The Problem We can see the following error while unpacking a package using rpm command; --- Preparing... ################################################## dbaastools ################################################## error: unpacking of archive failed on file /var/opt/xxxx/xxx/xxx/xxx/xxx.o.zip.xxxxx: cpio: read failed - Inappropriate ioctl for device How to correct this issue and to install the package successfully. The Solution RPM uses cpio as it’s archive format. This is the … [Read more...] about RPM : package installation Error : cpio: read failed
Understanding the Hadoop MapReduce framework
This post introduces the MapReduce framework that enables you to write applications that process vast amounts of data, in parallel, on large clusters of commodity hardware, in a reliable and fault-tolerant manner. In addition, this post describes the architectural components of MapReduce and lists the benefits of using MapReduce. MapReduce It is a software framework that enables you to write applications that process vast amounts of data, in-parallel on large clusters of commodity hardware … [Read more...] about Understanding the Hadoop MapReduce framework
lvdisplay error: “Failed to create directory /var/lock/lvm. File-based locking initilisation failed.”
The Problem On CentOS/RHEL 6.x with Logical Volume Manger, all the LVM commands return locking error immediately after boot up as shown below: # lvdisplay Failed to create directory /var/lock/lvm File-based locking initilisation failed. The Solution Above message is getting logged due to a check added in lvm code to verify if the path mentioned for locking_dir option in /etc/lvm/lvm.conf file is available or not and then print an error if the path used for locking_dir option is not … [Read more...] about lvdisplay error: “Failed to create directory /var/lock/lvm. File-based locking initilisation failed.”
CCA131 – Configure NameNode HA
Note: This post is part of the CCA Administrator Exam (CCA131) objectives series HDFS High Availability Overview A single NameNode is a single point of failure in a Hadoop cluster. You can experience HDFS downtime from an unexpected NameNode Crash or planned maintenance of NameNode. Having a NameNode high availability setup avoids these single points of failures. HDFS High Availability uses a pair of NameNodes One Active and one Standby Clients only contact the Active … [Read more...] about CCA131 – Configure NameNode HA