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10/30/2007

Network Latency



Latency due to distance = approximately 1ms per 100km

from: http://www.nessoft.com/kb/42

There are two *normal* factors that significantly influence latency
  • The latency of the connecting device. For a cable modem, this can normally be between 5 and 40 ms. For a DSL modem this is normally 10 to 70ms. For a dial-up modem, this is normally anywhere from 100 to 220ms. For a cellular link, this can be from 200 to 600 ms. For a T1, this is normally 0 to 10 ms.

  • The distance the data is traveling. Data travels at (very roughly) 120,000 miles (or 192,000 kilometers) per second, or 120 miles (192 km) per ms (millisecond) over a network connection. With traceroute, we have to send the data there and back again, so the latency will raise roughly 1ms for every 60 miles (96km, although with the level of accuracy we're using here, we should say "100km") of distance between you and the target.

10/11/2007

Internet Explorer::cannot post data to a non-NTLM-authenticated Web site


KB251404

SYMPTOMS
You cannot post any data to non-NTLM authenticated Web sites.

CAUSE
This issue can occur after you visit an NTLM authenticated folder.

RESOLUTION
add a value to the following registry key:
HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Internet Settings/
Add the following registry value:
Value Name: DisableNTLMPreAuth
Data Type: REG_DWORD
Value: 1

Also, turn off Enable Integrated Windows Authentication in Internet Explorer.
1. Start Internet Explorer.
2. Click Tools, click Internet Options, and then click the Advanced tab.
3. Under Security, click to de-select Enable Integrated Windows Authentication (requires restart), and then click Apply.
4. Close Internet Explorer.

To resolve this issue from the server side, configure the Web site to use either of the following authentication methods:
• Configure the Web site to permit anonymous access only.
• Configure the Web site to permit both anonymous access and NLTM authentication (Integrated Windows authentication).

VMWare::ESX::CPU Percent Ready


Good discussion about what this means and how to optimize CPU performance.
http://communities.vmware.com/thread/97303

"%Ready = Percent of time there is work to be done, and no physical CPU to do it on.

One rule of thumb that I use (saw it here some time ago) is that up to 5% Ready is OK, even normal; anything between 5% and 10%, best keep an eye on the VM and the host. Over 10% (for extended periods) you best be planning on taking some action.

One thing to keep in mind, if the VM is assigned multiple CPUs, they must both be scheduled on physical CPUs/cores simultaniously. This can cause you some headache (voice of experience here.) If only one CPU has work, both need to be scheduled, which is harder to do, and can take longer, increasing %Ready, response time, and reducing resources for other VMs."

"If you change from a multi-processor system to a uni-processor system you need to manually change the HAL on the Windows server after the conversion. To do this go into Device Manager after the machine first boots and discovers it's new hardware and then click on Computer then right-click on the processor and select Update Driver. Then select Install from specific location and then Don't search I will choose the driver to install. Then select show All compatible hardware and select the appropriate processor. For example, if you went from a dual cpu to a single cpu then select ACPI uni-processor PC instead of ACPI multi-processor PC. You will need to reboot once you change this. To verify what HAL you are using you right-click your hal.dll in c:\windows\system32 and select the Version tab and select Internal Name and it should say halmacpi.dll for multi-processor acpi and halacpi.dll for uni-processor acpi.

Next clean up all the non-present hardware after the P2V conversion. To do this go to a CMD prompt and type SET DEVMGR_SHOW_NONPRESENT_DEVICES=1 and then DEVMGMT.MSC and then select Show Hidden Devices. Delete any old grayed out hardware.

Next remove any vendor specific applications/drivers. For example on a HP server you should go to Add/Remove programs and remove any HP management agents, survey utility, array config utility, version control agent, etc. Also check your NIC and make sure there are no vendor specific drivers there (ie. teaming). Check the Services to see if all there is anything vendor specific related there and disable any services that are. "

10/08/2007

VBS::Parsing CSV


This is a great ongoing series:
Hey Scripting Guy!


Const ForReading = 1

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile("C:\Scripts\Test.txt", ForReading)

Do Until objFile.AtEndOfStream
strLine = objFile.ReadLine
arrFields = Split(strLine, ",")

If InStr(arrFields(1), "Everyone") Then
strContents = strContents & arrFields(5) & vbCrlf
End If
Loop

objFile.Close

Set objFile = objFSO.CreateTextFile("C:\Scripts\Everyone.txt")
objFile.Write strContents

objFile.Close