FAQ Updates – Nov/13/2010

Posted on in Categories FAQ last updated November 13, 2009

Our FAQ section is updated in last few days with new howtos:

  • Linux Network IP Accounting – I need to know how much data are transmitted on my ppp0 network or eth0 Internet links? How do I set IP accounting by address such as 123.1.2.3 and 123.1.2.4? How do I set IP accounting per Apache virtual domain? How do I set accounting by service port (http, smtp) and protocol (tcp, udp, icmp)? How do I record how much traffic each of the clients computer is using?
  • Linux / UNIX: DNS Lookup Command – How do I perform dns lookup under Linux or UNIX or OS X operating systems without using 3rd party web sites for troubleshooting DNS usage?
  • Linux: Find Out Which Process Is Listening Upon a Port – How do I find out running processes were associated with each open port? How do I find out what process has open tcp port 111 or udp port 7000 under Linux?
  • Google Apps Domain Create SPF Records For BIND or Djbdns – I work for a small business and outsourced our email hosting to Google. However, I noticed that spammers are using our From: First Last to send their spam messages. All bounced messages come to our catch only account. How do I stop this? How do I validate our domain using SPF? How do I configure a SPF for Google Apps domain using BIND 9 or djbdns?
    Mac Os X: Mount NFS Share / Set an NFS Client – How do I access my enterprise NAS server by mounting NFS filesystem onto my Mac OS X based system using GUI and command line based tools?
  • Explains: echo Command (echo $”string”) Double-quoted String Preceded By a Dollar Sign – I noticed that many shell scripts in /etc/init.d/ directory use the following syntax – echo $”Usage $prog start|stop|reload|restart”. Why a double-quoted string preceded by a dollar sign ($”string”) using the echo command under Linux / UNIX bash scripts?
  • Get intimated about our new howtos / faqs as soon as it is released via RSS feed.

mount forcedirectio: Disable Linux CIFS / NFS Client Caching

Posted on in Categories CentOS, File system, GNU/Open source, kernel, Linux, Linux Scalability, RedHat/Fedora Linux, Storage, UNIX last updated November 16, 2008

If your network is heavily loaded you may see some problem with Common Internet File System (CIFS) and NFS under Linux. By default Linux CIFS mount command will try to cache files open by the client. You can use mount option forcedirectio when mounting the CIFS filesystem to disable caching on the CIFS client. This is tested with NETAPP and other storage devices and Novell, CentOS, UNIX and Red Hat Linux systems. This is the only way to avoid data mis-compare and problems.