Eddie's Blog

Linux “No space left on device” Error

symptom:

a web site is down, but the httpd (in my case lighttpd) service started okay. restarting the service still has the same problem.

touch test_file, get the “No space left on device” error

df –h, show a lot of free disk space

Filesystem            Size Used Avail Use% Mounted on
/dev/sdb1              10G 2.8G 6.8G 29% /
/dev/sda1              99M   21M   74M 22% /boot
tmpfs                 125M     0 125M   0% /dev/shm

problem:

out of inodes

Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/sdb1             655776 655776       0 100% /
/dev/sda1              26208      38   26170    1% /boot
tmpfs                  31871       1   31870    1% /dev/shm

fix:

find the files of a certain size (e.g. great than three blocks in this example) to locate these files (in my case is the ruby session files in /srv/www/lighttpd/rails/tmp/sessions, the file name is ruby_sess.xxxxxxxx)

find / –size +3 –print

but rm –f ruby_sess.* failed because “bash: /bin/rm: Argument list too long” (see http://en.kioskea.net/faq/1086-unable-to-delete-file-argument-list-too-long)

ls ruby_sess.* | xargs rm get “-bash: /usr/bin/ls: Argument list too long”

find . –type f –name ruby_sess.* | xargs rm get “-bash: /usr/bin/find: Argument list too long”

finally find . –name “ruby_sess.*” | xargs rm worked

Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/sdb1             655776 122320 533456   19% /
/dev/sda1              26208      38   26170    1% /boot
tmpfs                  31871       1   31870    1% /dev/shm

Delete “Account Unknown” Local User Profiles

Issue:

On Windows XP or Server 2003, under Control Panel / System / Advanced / User Profiles / Settings, there are some “Account Unknown” user profile, but the Delete button is grayed out. And when try to delete the profile from “c:\documents and settings” folder, the error message is “Cannot delete NTUSER.DAT: It is being used by another person or program. Close any programs that might be using the file and try again.”

Solution:

Install “User Profile Hive Cleanup Service” (http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=6676)
Run uphclean.exe
Then the “Delete” button becomes available

Note: the User Profile Deletion Utility (delprof.exe) (http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=5405) cannot delete the “Account Unknown” profile, but it is useful to clean up the normal user profile when their account is still active. (delprof.exe /p /c:\\servername)

Microsoft Sender ID Framework SPF Record Wizard

Another useful tool to create the SPF record

http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/

Get-ADUser

Get-ADUser can get one or more Active Directory users; it’s part of Active Directory Module for Windows PowerShell. It’s similar to Get-QADUser in Quest’s ActiveRoles Management Shell (However, ActiveRoles Management Shell can be installed on the older operating system)

Active Directory Module for Windows PowerShell is part of the Remote Server Administration Tools (RSAT) feature on a Windows Server 2008 R2 server; and it’s part of the RSAT feature on a Windows 7 computer (download). However, it’s not available to install on any older operating system, including Windows Server 2008.

Basic usage of Get-ADUser

Get-ADUser –Filter { } or Get-ADUser –Filter *
Get-ADUser –Filter { } –SearchBase “DC=xxx,DC=com”
Get-ADUser –Filter { } –Properties * | Get-Member # to get all the properties; be aware of the property name is different than Get-QADUser cmdlet.
Get-ADUser –Filter {} –Properties <propertyname1,propertyname2> # to get the non-default properties to the pipeline

Exchange Server 2003 Public Folder Mail Enable or Disable Option

In Microsoft Exchange Server 5.5, all public folders were mail-enabled and hidden by default. In Exchange 2000 Server and Exchange Server 2003, folders can be mail-enabled or mail-disabled, depending on whether the Exchange Server organization is in mixed mode or in native mode.

If Exchange Server 2003 is in mixed mode, the Mail Disable is not available when right-click a public folder / All Tasks in Exchange System Manager, only the Mail Enable option is available (even the public folder is already mail enabled).

To access the Mail Disable option, change Exchange Server 2003 to native mode.

Reference:

PowerShell Credential Input

$cred = Get-Credential

will prompt the user entering the credential that can be used in other PowerShell script.

Or $cred = Get-Credential –Credential domain_name\user_name

to fill in the default user name.

Use $WhatIfPreference in PowerShell to Prevent Accidents

The default value of $WhatIfPreference variable is $false.
Adding “$WhatIfPreference = $true” to a script or the PowerShell profile
Now every cmdlet that supports a whatif switch will execute as the whatif switch is on
To overwrite the setting in a particular cmdlet, add –whatif:false in the cmdlet