What do you think about Amazon ElasticCache? (http://aws.amazon.com/elasticache)

High-Memory Quadruple Extra Large Cache Node (cache.m2.4xlarge): 68 GB memory, 26 ECUs (8 virtual cores with 3.25 ECUs each), 64-bit platform, High I/O Capacity cost 2.24$ per hour or about 1600$ per month!

For about 5000-6000$ you can purchase server with following hardware:
4x AMD Opteron 6128 / 2,00GHz Eight-Core (i.e. 32 CORES)
64GB ECC registered DDR3
2 * 80GB 2,5 Intel SSD with Adaptec RAID
1+1 1400W redundant (Hot-Swap) PSU
etc.

Now install here your favorite free Linux and Memcached and you are ready to go

Totally:

Server with better hardware (32 real 2GHz cores instead of 26 ECUs i.e. 8 virtual cores in AMZ, very fast DDR3 memory, redundant power supply and brand MB (Supermicro) instead of “well know instance lifetime issues in AMZ” etc) will cost you something like 3-4 month of AMZ instance rent! Sure, you can say like: what about Collocation cost? Hm… 1U server probably MAX 100$ per month (including some big traffic) etc.

Instead of Conclusion:

So you still think same about Amazon ElasticCache ???

Use Microsoft Hyper-V for virtualization?

Most probably you already store your virtual disks not in the system drive (i.e. not in drive ‘C’ for example), which is right approach (for performance and other considerations)

However not everybody know that in the C:\ProgramData\Microsoft\Windows\Hyper-V\Virtual Machines folder, Hyper-V actually store huge files (*.bin) for each virtual machine that you run on your Hyper-V host! That may be huge issue in case, if you have a lot of virtual machines in use and your system drive space limited. In addition, it also may introduce fragmentation problems, due to the fact that such files maybe created and removed each time you run your instance or when you create some snapshots etc.

So basically there are 2 main questions you may ask:
a) Why such files (*.bin) are created? And why they are so big? You may notice that size of such files actually equal to amount of virtual memory which you allocate for the virtual instance. So answer is simple – it just a place (such file) to store memory dump for Virtual Machine (instance) and required by Hyper-V
b) Can I get rid of such files? Answer – no In current version of Hyper-V it is not possible. However it is completely possible to move such huge files to separate disk(s) out from system disk! That SHOULD be done I think in any Hyper-V host anyway, in case if you have additional disks here. It is very easy to do that: on the first step of Wizard to create Virtual Machine, do not forget to change location for virtual machine from default one to location, where you have enough space to store both virtual machine memory dump and possible snapshots (in case if you plan to use them sure thing).

Recently got question from my colleague how I think it make sense to estimate time you will spend on bug fixing.
My colleague point 2 common ways how to do that:

a) Rough ETA x 4

OR

b) Periodical updates of ETA

I found both make sense to use together, so I recommend something like this:

1. Initially Estimate Rough ETA x2 or x 4 (depends how you feel yourself confident with given issue), with precision to hour / day (round value up).
   Forget minutes precision in all cases, forget hour precision in many cases. If you feel that issue takes 2 minutes to fix – put estimation 0. If you feel that it’s more like 15 minutes – put estimation 1 hour. If you feel it’s like 3-4 hours, put estimation 1 day. Don’t try to be precise. Instead it should be realistic.
   For example you think it takes 20 minutes to fix issue but you don’t have previous experience with such issues, so you got 20×4 = 80 minutes and round it up to 2 hours. Put value 2 hours into issues tracking software.  If your software support ranges, put here 20 – 80 minutes range.
2. If you use estimation precision as hour, you should update your estimation at least every hour, if you see that now you can measure ETA better.  If you use precision day, update your estimation at least ones per day. As more frequently you update your estimation as better. Sure don’t be too paranoiac - update previous estimation only if it changes significantly.
   For example say you estimate issue initially to 2 hours, so after first hour you working on issue, compare your initial estimation (2 hours) with what you think you have now (don’t forget about ETA x 4), for example now you feel that you need another 35 minutes to fix, so you multiple 35 * 4 and got 140 minutes = 3 hours. So you adjust your initial estimation from 2 hours to 4 hours (1 hour you already spend plus 3 hours you think it will take more).

Advantages:

1. You update your estimations frequently so even if you made serious mistake in estimation before, you quickly resolve. Fail quickly Your colleges and boss know where you are, so excellent transparency and you agile
2. You don’t care if you need to go to made coffee, go to rest for a while etc. You made your estimation SAFE enough (x2 or x4!) and you know that in next hour (or day if bug is complex) you always may update estimation again with more precise value.

In contrast to approach above, it can better in some cases (in most of cases in my experience)  to use “relative” measurement instead of time measurement.  Unfortunately in reality, seems it’s a bit more hard to begin with in some less agile teams. Another issue is that it’s just not every issues / bug tracking software support that.  In that alternative approach you think how much more complicated given issue is, compared to other issues you have / you done before and made your estimations relative.

P.S. Many people don’t like x4. Sure it’s completely optional. I saw people (and I am one of them ) that can do exact estimations in most of cases: in some cases because of luck, in other cases because of experience. In different cases because of both. Maybe it’s because usually they (and me) do that calculation x2-x4 in the mind and do not do it formally.
Taking to attention fact that it’s impossible to work 9-12 hours per day with same focus (hope my boss don’t read that Joke), it’s best way to always remember that effectively you have about 4-5-6 hours “crazy” time per day when you really can do your job with high focus and with maximum performance, while other time is required to prepare yourself for that “fight / micro-sprint”. So at least x2 should be applied in most of cases to be safe and I recommend to do it in your mind so your colleges get only one final estimation value, not intermediate result. It’s not about transparency. It’s more about ‘useless information’ for everyone, how exactly you calculate your estimations. Everybody may value you only by how your real time to fix issue was different to what you estimate.  And in most cases if that is not important! But what is true is that nobody care how you calculate ETA after you made your job done. People trust you because of results of your work, not because you do nice calculations, but it takes you 10x times more to fix issue than you think initially.

Just keep it simple, as always

Maybe I should go ….to PHP ?
(… I mean just go, not “go down” or “go up” or “go away from .NET” – read next why, really!)

Projects like Simple Cloud API (http://simplecloud.org) in PHP, together with Zend Framework and many other PHP related stuff  sometimes KILLS me, .NET developer / architect!

Why, WHY we do not have something like Simple Cloud API in .NET??? Or at least it’s not well known! Is it so hard to build and promote it ?? NO! Why it takes whole a lot of time to introduce ASP.NET MVC, if we do it so many years in Java or PHP !? Great .NET framework, tons of projects, but so limited amount of “innovative” open source projects in .NET!

Take a look, most of famous .NET open source projects go in same versions or even few versions behind if compare to corresponding projects from Java (see Lucene.NET for example), but do not introduce really “innovations” in the software programming! Some projects do not even exists in .NET space like Solr (i.e. you should use Java VM to run it)! Some projects like ASP.NET MVC comes much later other MVC frameworks in Ruby (RoR), Python (Django) or even PHP (Zend Framework)… And Microsoft last time spend whole a lot of effort to bring Java  / PHP into Azure… instead of increase sponsorship for example innovative OSS projects in .NET and by this push developers to go for .NET from other frameworks!

Should somebody build library like SimpleCloud in .NET ASAP!? YES! (please don’t tell me that I should build it ) Why?

Too many companies really need same thing to be able to abstract away Windows Azure or any other Cloud specific solution using some open source  libraries (like SimpleCloud in PHP) and made solution portable across Clouds, before they spend $$$ and stuck with one Cloud supplier forever See my post about this!
And too many developers really expect .NET platform to be more innovative !!!

P.S. sometimes innovations can waste your time / effort, if parent company stop support it – see my post about Silverlight

Silverlight Killed or? I don’t think so…
Unfortunately, in some sense http://mashable.com/2010/10/29/microsoft-silverlgiht-html made correct statement: “Microsoft Shifts From Silverlight to HTML5″ and that’s a FACT now!

Why this happens!?? Here is my thoughts:

1. Silverlight, like many other interesting concepts from MSFT was implemented with many technology related issues in early versions!
   Performance and fonts issues I can name as most important! I do NOT like how Silverlight apps looks at my TFT monitors (because of fonts issues), same like WPF applications! Sometimes, when I scroll something, it push me think that I should go to doctor to check my eyes again! (and same issues with fonts I see with IE9 beta, not sure MSFT will fix it someway or not before final release)
2. Silverlight supported on much less devices than HTML / CSS / JS / Flash and it seems like because it’s proprietary this can’t be changed in near future!
3. Development of Silverlight can be done right only using Microsoft tools like Visual Studio and Microsoft Expression Studio (some apps from it) that cost $$$
4. If you know Java, Python Django, RoR, PHP, Grails or any other language / platform / framework for web development, it’s much more easy to use HTML5 because you already know HTML / CSS / JS stack (as well as many web frameworks) than to move to something new like XAML / C# etc! I.e. basically only developers in .NET can consider using Silverlight, not other wide audience of Web developers! And while I can’t sure thing compare power of Silverlight and HTML5, MOST of required things can be done easy with nice JavaScript frameworks (think jQuery), HTML5, CSS3 etc.
5. Silverlight apps are always have big size! Sometimes there are even so heavy that web users probably will not wait so much time! Compare it to current compressed Javascript code and HTML5 compressed using standard gzip compression and / or different other compressors! What to feel it? Go to http://www.microsoft.com/windowsphone/en-us/buy/7/phones.aspx and check how long it takes to really get it in your browser!

I can give many other arguments around it, but generally when Silverlight out I made my choice – AVOID using it (as well as WPF, but that’s other story) for any live projects, until I will really feel the need of “all in one” web client application with really rich and heavy graphics / Video / Voice requirements!
It’s real fact that MOST of flash based sites, where site COMPLETELY was made in Flash FAIL, unless they touch some very specific area! I.e. it so easy to see that web users want “light” pages (HTML / CSS / Javascript) and not heavy as Flash / Silverlight get produced!
But again: I DO see big future anyway for Silverlight as really best framework to build RIAs out there in .NET space! More so, now it seems like Silverlight can take it place in WP7 development!

Just always you should ask yourself – are you sure you want to build (or customers ask you to build) RIA? Maybe you want to build super light, not heavy Web 2.0 (3.0) web site? Or may be you want to build something using only open / cross-platform technologies?
Than don’t even think about Silverlight, at least for now!