Lingo Explained: 2-way NDMP vs. 3-way NDMP

NDMP or the Network Data Management Protocol can be used to secure data stored on NAS filers (such as NetApp, Hitachi HNAS, EMC Isilon, …). The protocol has been developed by NetApp, before it became an open standard maintained by Storage Network Industry Association (SNIA).

The initial goal to develop the NDMP protocol was to provide a standardized framework which can be used by any backup software, to avoid the need to deploy custom agents on the NAS filer. When no agents could be deployed – which occurred in most cases -, the backup admin was obligated to secure the data by using a proxy server which mounted the volumes by using the CIFS or NFS protocol.

In general we can say the NDMP protocol supports two data protection mechanisms: two-way – and three-way NDMP. Continue reading

Lingo Explained: ACID Compliant SQL

ACID SQL stand for Atomicity, Consistency, Isolation and Durability.

Atomicity defines the way how the database handles changes in the database. If a part of the transaction fails, the entire transaction fails and the database remains untouched.

Consistency ensures the consistent state of the data throughout transactions. All write operations within the database need to be accepted with all predefined rules. It’s important to mention this is a database operation and do not guarantee consistency caused by faulty application level database operations.

Isolation ensures multiple transactions can be executed parallel as they were executed sequential. The content is not altered in the database, therefore a parallel query can be executed without interfering with the other query.

Durability ensures once the transaction has been completed, it’s committed into the database and will remain like this even when the servers encounters an outage.

Most relational databases (like Oracle and MSSQL) can be defined as ACID compliant.

Lingo Explained: ROBO

ROBO or Remote Office/Branch Office are offices in a different geographical location than the main office. These remote offices are mainly used to house sales representatives and to provide personnel a close-by-home work location.

Many ROBOs lack experienced IT personnel, adequate backup software/hardware and/or system backup and recovery capabilities.

IT infrastructure in small and mid-large remote offices are a common and problematic issue in every organization. As a general IT guideline, organization tend to keep the IT infrastructure in the remote office limited and provide ROBO solutions to ease the problem and daily management.

On June 30, 2015 23:59:59 a leap second with be inserted to Coordinated Universal Time (UTC)

Leap seconds are a periodic intervention in order to keep a system’s time of day close to the mean solar time. Without this adjustment, time defined by Earth’s spin drifts away from atomic time. Since this system of correction was defined in 1972, 26 correction interventions have been conducted. The last correction dates from 3 years ago: June 30, 2012 23:59:59.

Understanding the leap second (source: RedHat KB Article)

The basic time for mostly all of the world’s local time zones is called Coordinated Universal Time, UTC, which is derived from a bunch of atomic clocks which are distributed in several countries all over the world. The rotation of the earth is not very constant and varies a bit over time, while decreasing the mean rotation speed slowly. This is the reason why so called leap seconds are inserted into the UTC time scale, they adjust process of the UTC time to the real earth rotation.

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Lingo Explained: DIP, MIP & VIP

So what’s the difference between DIP, MIP & VIP?

DIP: Dynamic IP
IP Address received from a DHCP server.

MIP: Mapped IP.
A one-to-one mapping of one address to another. For example: from a public IP to a private IP.

VIP: Virtual IP
A virtual IP which maps the IP address to another address on the same system. For example Cluster IP’s. In Azure the term VIP refers to a public IP address mapping to a virtual machine (= which is basically a ‘MIP’).

Lingo Explained: BYOL/BYOD/…

In times of “Bring Your Own”, people still amaze me about the different spin offs and creativity!

BYOD : Bring Your Own Device
Also called BYOPC, BYOP, BYOT and other future spin offs.

BYOPC : Bring Your Own PC
The workstation used by the end-user is property of the user itself. The company defines by using a policy what the security measurements are (type of Anti-x, firewall configuration, and so on). Additionally IT departments tend to see the devices as ‘rogue’ and moves them to another security segment like a DMZ for example. Corporate applications are routed over a firewall or presented by using a presentation layer (web-based, app virtualization or a Virtual Desktop Infrastructure).

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Lingo Explained: tape shoe-shining (and how to avoid?)

Shoe-shining or backhitching – a term used in backup context – is a repeated back-and-forth-motion a tape device makes when the data flow is interrupted or is too slow. The process itself is destructive for the tape device, as well as for the tape cartridge.

A tape cartridge is a sequential medium requiring a continuous flow of data to keep the internal band in motion. When the data stream gets interrupted or the backup server is sending data slower than the tape drive processor, the tape device is obligated to stop. The stop  causes an offset of the writer and when resuming the device is required to position the writer back to the spot containing the blocks of the last write operation. The process: stop (end-of-data-stream), reposition (finding the right spot again), write (continue data stream) and repeat is what is called shoe-shining.

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Lingo Explained: Dilbert Principle & Peter Principle

The Dilbert Principle refers to a 1995s comic “Dilbert” by Scott Adams. In the cartoon Dogbert states “leadership is nature’s way of removing morons from the productive workflow“.

The principle actually refers to the systematically promotion in some companies of their least competent employees to management (generally middle management). The main goal of the promotion is to limit the amount of damage they can do without making a difference. Hereby they are creating a buffer between the employees and upper management.

Scott Adams told multiple times that managers do not understand the jokes in most strips. The problem is, most of the times they aren’t jokes and he’s trying to characterize how the management system really works.

As an opposite principle, we have the Peter Principle. The principle differs in promoting the most qualified person within the group regardless of the skills required in the new role. So employees only stop being promoted once they rise the level of their “incompetence“.

Lingo Explained: Cloud On-Ramp System

In the time of cloud, we come across various terms related to cloud or the former Application Service Providers (ASPs). A term I haven’t heard before is a “Cloud On-Ramp System”. The term originates from a Hitachi Development Story I read about centralizing data from remote sites to a central location or a cloud service provider.

The Cloud On-Ramp System as defined by Hitachi Data Systems (HDS) can be seen as a device which is installed on premise, but acts as a portal between your local IT environment and the cloud. The system uses the cloud to:

  • provide scalability and flexibility (capacity management);
  • avoid the need to backup your data once it’s stored in the cloud (data protection);
  • perform storage tiering by moving non-accessed data to the cloud and vice-versa (storage optimization);
  • combine the tiering process with pre-defined deletion rules (Information Lifecycle Management);

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