Monthly Archives: July 2014

XtremIO – Redefining Snapshots

Itzikr's Blog

A guest post by Tamir Segal, Senior PM

Snapshots is a technology that enables creating copies of volumes. XtremIO has developed a snapshot embedment that provides the ability to create space efficient snapshots that are managed as standard volumes in the cluster and have the same performance capabilities and data services as production volumes. In this post I provide a general explanation on legacy snapshot implementation, and explain what makes an XtremIO snapshot different.

Some Background

Legacy implementation of snapshot was based on technology called Copy-On-First-Write. The idea of Copy-On-First-Write is that once a snapshot is created, a new storage pool is defined in the system; every write to the production volume triggers a data movement operation to the snapshot pool:

· A new write is received by the system on LBA X

· The system reads the original data on LBA X from the production volume

· The system…

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Data Science as a Service: Driving Agility and Innovation to the ITaaS Model

EMC IT Proven

By Dr. Alon Grubshtein, Principal Data Scientist — EMC IT

This is a great time to be a data scientist –a bit like rock stars with all the fans always trying to catch some private time with us. While there’s is no clear definition of what a data scientist is (see related blog or view diagram of DS skillset) our take on this role is quite simple:

  1. Work with stakeholders to elevate high impact business related questions
  2. Find the means to answer these questions

This blog aggregates our collective experiences as members of EMC’s Corporate IT Data-Science-as-a-Service (DSaaS) team. Our team has been active since 2012, providing Data Science (DS) services to different business units as part of EMC IT’s transformation to an agile and innovative IT-as-a-Service model.

Although we aimed for a technical blog, we thought that the first post should provide a broader context to the…

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Fun with Linux UDEV and ASM: Using UDEV to create ASM disk volumes

Dirty Cache

floppy-disksBecause of the many discussions and confusion around the topic of partitioning, disk alignment and it’s brother issue, ASM disk management, hereby an explanation on how to use UDEV, and as an extra, I present a tool that manages some of this stuff for you.

The questions could be summarized as follows:

  • When do we have issues with disk alignment and why?
  • What methods are available to set alignment correctly and to verify?
  • Should we use ASMlib or are there alternatives? If so, which ones and how to manage those?

I’ve written 2 blogposts on the matter of alignment so I am not going to repeat myself on the details. The only thing you need to remember is that classic “MS-DOS” disk partitioning, by default, starts the first partition on the disk at the wrong offset (wrong in terms of optimal performance). The old partitioning scheme was invented when physical…

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