20. June 2016 22:33
I am working quite intensively with Raspberry Pi, and recently upgraded to both Raspberry Pi 3 and Raspbian Jessie, that was released during last quarter of 2015 and is currently the latest and greatest version of Raspbian.
The paramount part of my installation is Chromium browser, as these devices have to access website that is only compatible with Chromium-based browsers. And I found that if with previous Raspbian you could just run “aptitude install chromium” and it would install the browser, now you are getting message “no candidate version found for chromium” and nothing gets installed.
To overcome this issue and install Chromium, you need to download and install three packages. Here is the exact script of what you need to run in console: More...
10. June 2016 14:26
This sounds crazy. But when you move your website to the cloud, you get problems in things you were previously taking for granted. Like sending e-mails. Basically, the problem is that many e-mail servers, usually ones of big providers, have Azure, Amazon and other cloud provider IPs blacklisted. When you attempt to use SMTP service from your virtual machine in Azure – in many cases it fails to deliver. This means, that your Azure machine can not act as mail server and shouldn’t attempt to deliver messages to recipient SMTP server directly.
Why would you use SMTP service at all? Well, mainly for the sake of performance. Your web application, be it ASP.NET, PHP, Ruby or whatever, will benefit from saving the outgoing e-mail message as text file somewhere on local hard drive, instead of trying to deliver it using TCP/IP, even if that’s done in asynchronous method.
26. August 2013 13:29
As a note to system administrator – what to do, when your one and only administrators account is locked on your SQL Server.
You need to perform 5 quick steps. More...
16. August 2013 00:00
On second Tuesday of each month Microsoft releases batch of patches for Windows and everything. Some of these patches require restarts of machine. Sometimes during the process machine can shut down instead of restarting. Sometimes the machine can’t even shut down properly. Yet in many cases production servers have "Install updates automatically" setting turned on. This is a sort of Russian roulette.
Morale: do not enable automatic installation of updates on production servers or machines you can’t switch on immediately.
11. August 2013 08:33
This is a CPU usage graph of a Windows Server 2008 R2 machine, with all latest patches applied, and Internet Explorer 10 left opened for a few days. It had only two pages opened, both are Microsoft’s own support pages with no active content.
Remote session (RDP) was opened for about 5 days, and every hour Internet Explorer process took more and more memory and CPU, until it took most resources from server.
29. May 2013 12:40
I had two problems with my Windows
Me 8. At least two which were clearly bugs in operating system and not a usual Dell hardware failure. And seems like both of these problems had the same solution, which potentially should be able to fix some other issues with Windows 8. More...
24. February 2013 22:23
In SQL Server 2012, we have 4 main options for High Availability: Database Mirroring, Failover Clustering, Availability Groups and Log Shipping. All but Availability Groups (AG) are available in SQL Server 2008 as well. Today we’ll review Availability Groups and how to create and use them.
Before we begin, make sure you understand what is Windows Server Failover Cluster (WSFC). I covered it almost a year ago for Windows Server 2008 R2 and SQL Server 2008 R2, and you’ll need WSFC in order for AG to work.
A few points about Availability Groups to make sure they are what you are looking for:
- Availability Groups are not share-nothing scalability option. They are using shared storage, such as storage area network (SAN), although it’s not a requirement. We’ll speak about share-nothing scalability later.
- For AlwaysOn Availability Groups, you need SQL Server 2012 Enterprise edition or higher. Business Intelligence edition or Standard won’t do.
- AG provide failover with up to 5 readable nodes.
- AG provide you with something like load balancing option, but AG is not NLB. Also, all nodes can work independently, i.e. you can still connect to them to retrieve information. Only the primary node can change information in the database.
- AG does not require working in the same IP subnet, but it requires Active Directory domain. This means, that you can have geographically remote nodes participating in one AG, but they must be members of the same AD domain.
In case of multi-subnet cluster, you’ll have to implement the file replication solution on your file servers to synchronize the data.
- AG is database-level, as opposed to node-level failover cluster. AG serves group of databases, unlike the simple database mirroring, with 4 replicas instead of one.
Overall, the AlwaysOn Availability Groups are conceptually similar to database mirroring, but provide more advanced functionality and security.
16. February 2013 07:00
If you are developer, then you work with relational databases as well. And if you work in a Windows world, most likely your system of choice is Microsoft SQL Server.
With every new DBMS release we find something that changes the way we solve common problems in new solutions. SQL Server 2012 is no exception.
In SQL Server 2012, instead of just enhancing the productivity and robustness of the server, Microsoft solved a number of architectural problems we previously had to deal with in our applications when working with SQL Server.
Problems like saving files in databases, load balancing database clusters and simple restoration of data, finally got the minimum viable solution, which should only improve with time. More...
6. October 2012 22:22
This article is about free software I made to automate the deployment of exported Hyper-V machines. More precisely – Hyper-V machines of labs for Microsoft Official Curriculums (MOC), used by students at Microsoft official training classes. It should be interesting for MCTs (i.e. Microsoft Certified Trainers) out there, whose job is to deploy labs in form of Hyper-V virtual machines, as well as for system administrators having the same duty of periodic installation of Hyper-V virtual machines. The installation procedure of a pack of Hyper-V machines could be extremely time consuming. Or should I say - used to be.
I will speak about it as about the solution for a lab deployment problem, but if you are working with other virtual machines, just think about the similarities with your scenario.
27. September 2012 14:32
Well, the “unexpected” should be put into quotes, because if you went through the Windows 8 training, then you have some ideas about how it works, but even if you did the training, some things are not clear until you crash at them at full speed.
As I mentioned before, Windows 8 now suspends applications which loose their focus. In Metro applications framework you, as developer, can deal with suspension notice and make sure you save the current state of the application, and you could use application manifest to create exception from the rule. Say, if your application is a media player or a browser.
However, it turns out that Metro applications are not the only ones to be suspended. More...