Category Archives: Uncategorized

Erasure Code

Posted on December 19, 2018 by ahmadhassaan

In Distributed File Systems, the Erasure code is the engine behind achieving redundancy to tolerate against node failures. It split the block into k units and using some coding (Reed Solomon) it generates more m units. to illustrate let’s assume … Continue reading →

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ACID , CAP , and BASE

Posted on December 14, 2018 by ahmadhassaan

Quick summary : Relational DBs(Oracle , MySQL ,) depend on ACID . NoSQL DBs (AWS DynamoDB, Cassandra, and Google BigTable)depends on the updated version of CAP, known as BASE. More Details: In DB world old days, as the relational database … Continue reading →

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What is iSCSI and How to Configure in Solaris 11 and Linux.

Posted on March 10, 2017 by ahmadhassaan

Before we define iSCSI,we must know what is SCSI itself. SCSI: Small Computer Systems Interface, is a family of protocols for communicating with I/O devices( especially storage). SCSI protocol is being used by servers to communicate with storages over various … Continue reading →

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Solaris 11 Link Aggregation

Posted on May 16, 2016 by ahmadhassaan

Definition : consists of several interfaces on a system that are configured together to form a single,logical unit. So ,if i have two interfaces with 10Gbps speed,by aggregating them ,we ‘ll get a single interface with 20 Gbps speed and … Continue reading →

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Migrating OVMM ( Oracle VM Manager)

Posted on February 29, 2016 by ahmadhassaan

It was a painful task for me to migrate OVMM from one machine to another ,as no clear document with descriptive steps. So ,I have rendered some documents and some googled points  into the following steps which works fine with … Continue reading →

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Replace disks on veritas volume manager and increase filesystem online

Posted on January 21, 2016 by ahmadhassaan

It is usual to get a request to increase volume sizes or replace old disk with a new one,with no downtime for the activity. Task: a mount point (/u03) needs more  200GB space the (/u03) is mounted on vxvm volume … Continue reading →

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Generating Certificate for iLOM and XSCF

Posted on January 13, 2016 by ahmadhassaan

  To get a certificate, we do these steps: 1- generate private key (myprivkay.key) 2- generate  Certificate Signing Request (CSR ) from private key. (mycsr.csr) 3- Generate a SSL certificate from CSR file (mypubkey.cert) 4- import both private key (myprivkey.key) … Continue reading →

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Red Hat Enterprise Linux to Oracle Solaris 11 Comparison

Posted on December 11, 2015 by ahmadhassaan

Linux administrators can kick start their learning experience when planning Oracle Solaris deployments by reviewing the following summary between Oracle Solaris 11 features and Red Hat Enterprise Linux 7 features. For more information about the Oracle Solaris 11 features, be … Continue reading →

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svm on solaris 10 x86 (ufs )

Posted on August 7, 2015 by ahmadhassaan

while I was playing with a solaris 10 vm under VirtualBox , i changed the disk from port3 to port1 ,this should affect disk path to be (c0t0d0) ,before it was (c0t3d0). So ,it is ok ,all i need is … Continue reading →

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Some SUN servers like (Blade X6270 ) uses lsi raid controller to manage disks. Important Hint: megacli will not work with lsi 1064 and lsi 1068 controllers The problem here will come if we have  faulty disk and wants to replace … Continue reading →

Posted on July 20, 2015 by ahmadhassaan | Leave a comment