Thursday, 26 May 2011

Basics of Memory Management

Reading all these article in Wikipedia and different blogs about memory management technologies put me to shame. I literally didn't know anything about it and would probably never find it out if I stayed pure networking guy. Since I want to go a bit deeper into vSphere memory management (Memory Virtiualizaion, Virtual MMU, TSP) in the my next articles, today I need to build a foundation on top of which I can put additional layers later.  I will try to explain new stuff in the same way I would like it to be explained to me one week ago.

I need to start with explanations of some definitions and basic principles of memory management.
Mostly all modern applications/OS work with virtual memory.  None of them has any idea where its actual memory is located. Each process truly believes that it has it own address space.

Tuesday, 24 May 2011

NUMA - Non Unified Memory Access

Last two days I spent quite a lot of time on reading absolutely new topics for me - NUMA, Transparent Page Sharing, TLB, Large Pages, Page Table, and I hope within this week I will make several posts on each of these technologies and how they work together. I have done some tests playing around with Large Pages in ESXi and would like to share this information as well.
I want to start with an explanation about what the NUMA is and to what extent ESX is NUMA-aware. There is a huge amount of information about NUMA in the Internet and probably you are already aware about it, so please let me know if I made any mistakes in my topic.

NUMA stands for Non Unified Memory Access and has nothing to do with Romanian music band and its song "Numa, Numa, yeah". Currently it is presented in Intel Nehalem and AMD Opteron processors. I always assumed that CPUs equally share memory, however this is not the case with NUMA.

Tuesday, 17 May 2011

Virtual MS Failover Cluster migration between storages

Recently we  had a task for full data migraiton from old HP MSA 2312 FC to HP EVA 6400. The MSA was used mostly for VSphere and hosted several VMFS datastores. Basically, the whole procedure for migration was quite simple though it had to be done very carefully.

However, we faced a challenge. I have had experience on migration of VMs  between storages and VSpheres at the same time (and even the between different versions - 3.5 and 4.1), and basically I might easily make a draft migration plan. However this time there were 2 Production Virtual-Virtual MS Failover Clusters running in that VSphere. One failover cluster was running MS Windows 2003 and Exchange Server. Another cluster was running Windows 2008 Failover Cluster and SQL Cluster. Both clusters were using RDM disks in Physical Compatibility mode. Since services running on these cluster were quite important for  we couldn't have long downtime.

Thursday, 12 May 2011


Hello to everyone.

My name is Askar Kopbayev. I work as Network & Infrastructure Cooridnator in Agip KCO and this is my first blog ever. I am planning to write mostly about VMware, for the simple reason that it is my favourite technology nowadays, and my preparation to VCAP-DCA exam, nevertheless I will probably post more about networking, storage and other topics I work with.

I have been thinking about blogging for a quite long time, however, I couldn't find appropriate theme that would be interesting to write about. Last week I had a trip to Madrid to HP Technology&Work on Tour event (I will definitely write about it in my next posts) and during one of the presentation I understood couple of things:

1. I want to be Datacenter Administrator which means I want to be storage, networking, server administrator. I want to be involved to all activities about data centers.

2. Blogging might help me trace my own progress towards VCAP and also help on structuring the new thing I learn. You all know how clear things become when you explain them to another person.

My experience includes 5 years of networking experience with Cisco products (CCNP, CCSP), some Microsoft skills and qualifications, which are quite obsolete - MCSE 2000, and half a year of Vsphere experience along with VCP certification.

Btw, my mother tongue is russian so you can always write me or comment in russian as well.