Blog (at) Mreza.Info

Exres.dll is Resource DLL of Exchange Server. It acts like "proxy" in communication between Windows Cluster Services and Exchange Services. Windows Cluster service communicates trough Resource Monitor to Exres.dll, and Exres.dll communicates with the Exchange services. This .dll is responsible for reporting failures in the cluster and bringing resources onnline/offline.

Describes the installation and configuration of a High-Performance Computing (HPC) cluster for a dual boot of Microsoft Windows Compute Cluster Server 2003 and the Linux OpenSuSE Operating System (OS).

Download it here.

When making a platform decision, many organizations focus on key attributes, such as total cost of ownership (TCO), reliability, and support. The chart below helps put these key criteria in perspective as you compare the advantages and disadvantages of Windows Server versus Red Hat commercial Linux.

Source: Compare Windows to Red Hat

Well... If you run Disk Cleanup and if you select Hibernation File Cleaner it will disable hibernation in Windows Vista.

To re-enable hibernation run this from command line. And don`t forget to run as Administrator :)

powercfg -H ON

To disable hibernation in Windows Vista run this from command line as Administrator.

powercfg -H OFF

I just found this short demo of new virtualization technologies in Longhorn. It covers:

• Running virtual machines on Longorn Server Core
• 8-core virtual machine
• System Center Virtual Machine Manager
• and some tricks... like hot-add network adapter :)

We all know that Microsoft products such as Exchange Server 2007, SQL 2005 x64 can really benefit from x64 platform. But what about Active Directory? Similar to the limitations of Exchange Server 2003, Active Directory suffers from the 2GB virtual memory limit of 32bit operating systems. That`s not a problem for small AD deployments but it can be a real issue for large deployments with a LOT of objects. With large number of object it gets difficult to cache the Active Directory database and authentication requests and queries leads to excessive paging and a slowdown in performance.

So if you are planning or working with a large Active Directory deployments than go for x64 platform. Especially now when prices for 32 and 64bit platform are almost the same. [Y]

Let me quickly try to explain about 2GB memory limit in 32bit operating systems.  You probably all heard about the Windows 4GB memory limit. When talking about performance tuning and server sizing, people are quick to mention the fact that that an application on an 32bit Windows system can only access 4GB of memory.

What does that really means?

A 32 bit processor uses 32 bits to refer to the location of each byte of memory. 2^32 = 4.2 billion. That means a memory address that`s 32 bits long can only refer to 4.2 billion unique locations in memory (that`s 4GB of memory). (Source: Wikipedia)

In the 32bit Windows each application has its own »virtual« 4GB memory space. This 4GB memory space is distributed into two parts, with 2GB dedicated for kernel and 2GB for application usage. Each application has its own 2GB, but all have to share the same 2GB kernel space. Using the /3GB boot.ini switch is even worse in some cases (Terminal Server for example). This switch changes the amount of memory for application and kernel environment. It gives 3GB of memory for application environment and »only« 1GB of memory for kernel. But if you are using /3GB boot.ini switch for SQL Servers you can gain performance since it`s a memory-intensive application (and not kernel).

There is a difference when systems are booted using /PAE switch. Physical Address Extension (PAE) is an Intel provided memory address extension that enables support of up to 64GB of physical memory for application. PAE allows the most recent IA-32 processors to expand the number of bits that can be used to address physical memory from 32bits to 36bits trough support in the host operating system for applications using Address Windowing Extension (AWE) application programming interface (API). AWE enables programs to reserve physical memory as non-paged memory and then to dynamically map portions of the non-paged memory to the program`s working set of memory. This process enables memory-intensive programs, such as I already mentioned before (SQL – databases), to reserve large amounts of physical for data without having to be paged in and out of a paging file for usage. Instead the data is swapped in and out of the working set and reserved memory is in excess of the 4GB range.  Additionally, the range of memory in excess of 4GB is exposed to the memory manager and the AWE functions by PAE. Without PAE, AWE cannot reserve memory in excess of 4GB.

I`m really busy lately. I have some projects involving Microsoft Exchange Server 2007 Beta 2 (Rapid Deployment Program). But I will talk about that some other time... What I can say for now is that Exchange 2007 really ROCKS (or FYDIBOHF23SPDLT if we take the name from New Exchange Admin Group [H])!

It`s not a new thing but a lot of people never saw it on Windows (but they are familiar with it from Unix or Novell).

So what is Access-based Enumeration?

Windows Server 2003 Access-based Enumeration makes visible only those files or folders that the user has the rights to access. When Access-based Enumeration is enabled, Windows will not display files or folders that the user does not have the rights to access. This download provides a GUI and a CLI that enables this feature.

You can download it from here: Windows Server 2003 Access-based Enumeration

These step-by-step guides provide instructions for deploying or migrating to Windows Vista. These guides also describe how to configure security, monitor performance, and manage printers.

Overview
These step-by-step guides will assist IT Professionals in deploying or migrating to Windows Vista. These guides will also provide step-by-step information on how to control device installation using Device Management and Installation (DMI) and manage ADMX files. There are also step-by-step guides to help you protect data using BitLocker Drive Encryption, to administer the TPM Security Hardware in a computer using Trusted Platform Module (TPM) Services, and to help deploy better-managed desktops and mitigate the impact of malware using User Account Control (UAC).

Download: Windows Vista Step-by-Step Guides for IT Professionals v2.9

Today I spent some time playing arround Windows Vista Beta 2. There is one interesting thing that i found out. It has ASLR (Address Space Layout Randomization) and it is turned on by default. It is a great against defense against buffer overrrun exploits called address space layout randomization. This defense is of course not a replacement for insecure code but it is indeed a usefull in Mult-Llayered defense. So remote exploitation of overflows has just got a lot harder.

So what is ASLR?

Address space layout randomization (ASLR) is a computer security feature which involves arranging the positions of key data areas, usually including the base of the executable and position of libraries, heap, and stack, randomly in a process' address space. This hinders some types of security attack by preventing an attacker being able to easily predict target addresses, for example attackers trying to execute return-to-libc attacks may find it harder to locate the code to be executed. Several security systems implement ASLR, notably OpenBSD and the PaX and Exec Shield patches for Linux.

ASLR relies on the low chance of an attacker guessing where randomly placed areas are located: the odds are 1 / 2b, where b is the number of bits of entropy used to determine the position of the data area. In many systems, 2b can be in the thousands or millions; on modern 64-bit systems, these numbers typically reach the millions at least. Some systems implement Library Load Order Randomization, a form of ASLR where the order in which libraries are loaded is randomised. This leaves libraries at unpredictable positions: the chances of an attacker correctly guessing the location of a library is 1 / n, where n is the number of libraries loaded.