New Theme
So, blog.jim80.net has a new theme installed. It’s called Open Sourcerer 1.4 by Alan Lord, and it’s got one thing iNove 1.4.5 by mg12 didn’t, flexible width columns. Well, technically, iNove could be made to adjust according to screen resolution, but the resultant view on a widescreen wasn’t very pretty. if anything it just looked silly. Thus, I present Open Sourcerer. It’s easier on the eyes, if it is a bit plain. Frankly, the column width bit is a necessity for a post I’m working on. Hard coded to the previous size, it would have been a nightmare to read. Trust me, I’m doing you a favor.
=P
Sean-One – Log Ya Mods
So, one of my admin colleagues, Sean, decides to write up some nerdy-lyrics to a rap song, and I thought it’d be a colourful addition to this blog.
This is the first verse to KRS-One – Build Ya Skillz. Lyrics possibly NSFW.
Sean-One – Log Ya Mods
2010 erplefoo industries (erplefoo@gmail.com )Check, I control your realm with one password I speak
And spread your auth all over like a raid level 5’s disk seeks
Admins get kicked in they mouth with cleats
Kuz their plans failed to reach servers at the beach
Have a seat quick, I’ll set up your account bits, time to complete shit
Looks like I need to reset shit, I mean set perms properly
I can feel myself becoming an admin monopoly
Others will copy mtree but apply my shit sloppily
Shocking me with static straps not entirely attached to me
Electroshock it seems to be
My true identity is never meant to be
Exposed in the sun that shit’s bright daily(chorus)
But admins mod too much shit and fuckin’ forget to log it
LOG YOUR MODS
Admins talk too much shit
And send quotes up to reddit
LOG YOUR MODS
You can follow Sean on Twitter at @sdfoo
Why 100Mbps Does Not Mean 100Mbps Transfer Rates
You will not always see 100Mbps upload/download speeds even with a 100Mbps port. Much of the slowdown occurs because as packet travel distance increases, so does latency, which has a large detrimental effect on large file transfers. For smaller files, like those associated with not-too-graphical web pages, this has less impact. Without getting too technical, this is because file transfer protocols that use TCP require that the recipient respond with confirmations of data received, and this is one reason that file transfers over longer distances are slower, in direct proportion with the increase in response times.
See http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/ for a more in-depth discussion on this.
Most download accelerators are able to increase transfer rates by simply employing multiple TCP pipes that dump into the same file. This doesn’t solve the TCP window size problem, but takes advantage of what the uplink is capable of handling. Most modern browsers do this automatically, so download accelerators are really not a necessity any more.
You may wish to optimize your per-TCP connection transfer rates though. To do so, determine your optimal TCP window size based on the expected latency of your most bandwidth intense client-base (see the calculator at the above link). Then, based on that, adjust your TCP/IP stack to adjust below:
To tweak Windows 2008 TCP Window Scaling, please refer to the following:
http://www.minasi.com/newsletters/nws0802.htm
http://www.msfn.org/board/heres-why-tcpwindowsize-does-not-work-vista-t87969.html
Note that Windows 2008 doesn’t allow you to tweak settings like 2003 did. You can make the system adjust it “more aggressively,” but you can’t hard code numbers in.
To tweak Windows 2003 TCP Window Scaling, please refer to the following:
http://articles.techrepublic.com.com/5100-10878_11-5034413.html
You may wish to also try: http://www.speedguide.net/tcpoptimizer.php
To tweak Linux TCP Window Scaling, please refer to the following:
http://www.speedguide.net/read_articles.php?id=121
Note that many other factors come into play for bandwidth calculation. In a hosting environment, your server must compete with other servers in the data center to reach the core routers and from there, must concentrate in various nodes and exchanges to reach a packet’s destination. Along the way, routers must prioritize and queue packets for transmission. We can check the health of this process by performing a traceroute between “slow links.” Network congestion at any one of these nodes can reduce overall transfer rate. On either one of the endpoints, disk I/O, or other system stress may be a bottleneck.
All in all, an 100Mbps, or even an 1000Mbps uplink will not provide transfer rates greater than what the network fabric in between the source and destination can handle, and not greater than what the server / client can negotiate within the TCP pipe.
#18 Feb 2010 – Edited for spelling/grammar.
Setting up Hyper-V with NAT
This post was originally posted by me at http://forums.serverbeach.com/showthread.php?t=6411.
I’ve edited out the ServerBeach specific stuff and will post pictures…. soonish.
The following link has some great pictures not included here. http://sqlblog.com/blogs/john_paul_c…h-hyper-v.aspx
I’ll add some nice little pictures here once I get some screenshots together.
CONFIGURE HYPERV
1. Configure an “Internal” HyperV network
2. Set each Virtual Machine to use the Internal network and assign them and your HyperV host on the correct subnet (in this example 10.0.0.1 for the host and 10.0.0.10 for the VM).
ENABLE ROUTING AND REMOTE ACCESS ON THE HOST MACHINE
1. Click -> Start -> Administrative Tools -> Routing and Remote Access
2. Right Click on Server#### (local) -> Configure & Enable Routing & Remote Access
3. Click -> Next on Welcome Window
4. Select Custom Configuration Click -> Next
5. Select NAT Click -> Next
6. Select your public interface
7. Select your Internal HyperV interface
8. Select “I will set up name and address services later” Click -> Next
9. Click -> Finish
CONFIGURE ROUTING AND REMOTE ACCESS ON THE HOST MACHINE
1. Routing and Remote Access should be running on the server now
2. Expand out the Server
3. Expand out IP Routing
4. Select NAT/Basic Firewall
5. Right-click your public interface. Select properties
7. Network Address Translation Properties Window will open
8. Select Radio Button for “Public Interface Connected to the Internet”
9. Select the check box for both “Enable NAT on this interface”
10. Click on the Address Pool Tab
11. Click the Add button and add your secondary IP addresses. The “Start Address” and “End Address” will be the same in most cases.
*NOTE* You do not want the secondary IP address configured in the TCP/IP Properties of the Host machine.
12. Click the Reservations button and enter your static IP mappings. That is, specify that you want traffic on your secondary IP mapped to your VM’s internal IP.
13. In services.msc, make sure that RRAS is set to start automatically and Windows ICS is disabled.
NOTES #1
When configuring and experimenting with the RRAS firewall, create a batch file to stop the service in case you forget to allow RDC or otherwise render the system inaccessible.
Code:
net stop “remoteaccess”
Then add the batch file to the scheduler and have it run some time after you apply your changes.
NOTE #2
RRAS is really finicky about the interfaces installed on the server. If an interface is changed in any significant way, it’ll have to be disabled and reconfigured.
Hyper-V is also similarly finicky about its virtual networks. I can’t count the number of times I had to remove and recreate networks. Thankfully, this was rather painless with only one VM to propagate changes to.
If you should encounter any difficulties with adding your additional VMs to the server, try resetting HyperV networking, individual VM network binding (in the VM’s settings), confirming physical host interfaces, and then reconfiguring RRAS in this order.
NOTE #3
Those who have had HyperV configuration problems solved it by disabling TCP/Offload Engine. Symptoms include, RRAS just not working, or working sporadically. If in doubt, disable TCP/Offload Engine
http://social.technet.microsoft.com/…8-d22aca6154ee
http://support.microsoft.com/default…b;EN-US;904946
So if this applies to you, run on the host and on any 2008 VMs:
$ netsh int ip set global taskoffload=disabled
and add the following registry key to any 2003 VMs:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\Tcpip\Parameters\DisableTaskOffload
This is a DWORD entry that should have a value of 1.
Windows XP Mode
If compatability mode is not enough for you, check this out:
http://www.microsoft.com/windows/virtual-pc/download.aspx
You can install a Windows XP VM in Virtual PC on your Windows 7 workstation. The cool part is the integration. Install a Windows XP application, and it’s automatically integrated into your Start Menu in Windows 7.
I am so geeking out right now.
