421 reputation
25
bio website loadrunnerbythehour.com
location North Carolina
age 46
visits member for 3 years, 1 month
seen May 5 at 13:30

One half of the dynamic duo at PerfBytes radio, PerfBytes


Sep
2
comment What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
For many organizations the use of virtualization, particularly in Microsoft environments, is a lazy solution for platform consolidation. They do not see a clear path to retain the domain or internet namespaces resident on client computers for access to services on remote hosts and so virtualization is an easy solution. Where you have the right knowledge you can easily roll up dozens of individual computers to a single host without virtualization, retain the namespaces, even retain the IP addresses if you wish, and keep client computers blissfully ignorant of the change.
Sep
2
comment What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
Databases, JVM's, etc... are defined as guest operating systems for the fact that they provide their own namespace for access to resources, they manage resources directly in a block and can run software defined for these environments. Databases also tend to have their own file systems for the storage of data. I am not totally virtualization averse as I use the technology every day as a part of a services delivery practice, but where performance is the primary concern (as it is in my field) I do not recommend or deploy virtualized solutions.
Sep
2
comment What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
With the bean counters making the push, the trend is oversubscription on the virtual machine hosts, which pushes the hypervisor decisions on resource allocation to almost universally poor to all of the guests. The hypervisor layer is also not as robust on the throughput front as the standard OS drivers so you do suffer a loss in maximal throughput vs the standard non-virtualized interface.
Sep
2
comment What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
My comments come from direct in-the-field observations of successful and failed migrations to virtualization solutions over the past decade as a performance engineer. There are tons of bad database apps out there whose promiscuous use of hardware masks performance issues. Add virtualization and those issues come to light. If you have an app which demands a precise clock for timing or audit purposes, then with the clock float in software virtualization you are out of the hunt.
Sep
1
answered What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
Aug
19
answered Inducing artificial network latency in Hyper-V
Aug
12
answered Performance impact of monitoring a performance counter
Aug
9
revised Using R for crunching system data?
added 2 characters in body
Aug
7
comment Ubuntu Apache server slows down when connected to the internet
Grab Yslow or HTTP watch to see where the slowness is coming in the request fufillment.
Aug
5
awarded  Teacher
Aug
4
awarded  Editor
Aug
4
revised Ubuntu Apache server slows down when connected to the internet
added 2283 characters in body
Aug
4
answered Is there an algorithm to help figure out how many machines should host a website?
Aug
4
answered Using R for crunching system data?
Aug
4
answered Ubuntu Apache server slows down when connected to the internet
Aug
3
answered Load testing wireless LANs
Aug
1
answered Network load tester app
Aug
1
answered Network testing: looking for any test daemon and client combination to measure firewall load with 500..2000 incoming connections
Aug
1
answered Can anyone please recommend any good Load Testing software?
Jul
31
comment Stress test a server for simultaneous connection
Yep, that's what I get for math in head vs writing it out, order of magnitude off. Thanks for catching it. But what you have done is made my initial point so much better....who has 15 megabits of h coming out of their streaming server. If you get to this level then you are going to need to stream using a CDN proxy solution or you need a different streaming model.