421 reputation
25
bio website loadrunnerbythehour.com
location North Carolina
age 46
visits member for 3 years, 3 months
seen Sep 30 at 18:06

One half of the dynamic duo at PerfBytes radio, PerfBytes


Sep
30
comment Proof that hibernating the server over the weekend is not a good practice
Take the WOL utility which you are using and stage this utility on a server which us up 24x7 and has scope to send the WOL packet to the host in question. If Windows, use the 'AT' command to schedule the execution of your command line WOL utility to wake the server in question. If LINUX/UNIX, then use 'cron' to set a scheduled event to kick off the WOL utility at a particular time.
Sep
29
comment Proof that hibernating the server over the weekend is not a good practice
I concur on no need to be on for WOL to kick in. You can also use WOL as a scheduled task, kicking it off at, say, 2:30am on Monday, backing up your system and then having your system available for users at the beginning of your workday
Sep
14
comment Windows 7 naming problem
That is a reasonable assumption and one I considered, but I opted in the end to take the poster's literal expression of all networking under DHCP
Sep
14
comment Server configuration - dealing with 350 similtaneous use
Yes, it is preventable. The number of handshakes back and forth for different elements combined with the sizes will impact severely your network performance in such a case. Minimize the number of file content elements, make them as small as possible, even enabling compression on the server. Likewise with the graphics, pick a network friendly format and optimize the color pallete to eliminate extra weight. If SSL is involved, only use it where Personally identifiable information is present, otherwise it adds overhead to the site. Expand the server cache so it hits disk less. ...
Sep
2
comment What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
Do not get me wrong, I am not trying to "blame" virtualization here. I am a very happy user of the same technology in specific areas of my IT infrastructure. There are bad IT decisions chasing cost savings being lead by non-IT folks and bad applications that are leading the way to poor performance in virtualized/cloud environments. These bad decisions keep my organization very busy.
Sep
2
comment What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
I only have a decade worth of in-the-field observations to draw from. Where I am generally called primarily falls into two categories related to poor performance, environments are horribly oversubscribed, with IT decisions being driven by accounting managers unfamiliar with technology and with applications which are poorly designed/have high clock dependencies which are not well sorted for performance. In all cases the delta from physical to virtual us more than a few %. In some cases both are present. My observations may be biased by spending most of my time fixing these issues.
Sep
2
comment What are the drawbacks of running a database inside a virtual machine? How do I overcome them?
"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?
Unfortunately neither Microsoft nor Novell really embraced fully the directory model for both administrator and user namespaces as Banyan pioneered, for if they had platform consolidation would have been very easy. An admin could then simply migrate a service from one host to another and retain the same logical namespace as resolved by the directory server without users having any knowledge of systems being changed in the background.
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.
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.
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.