Linux and other Unix-like operating systems use the term “swap” to describe both the act of moving memory pages between RAM and disk, and the region of a disk the pages are stored on. It is common to use a whole partition of a hard disk for swapping. However, with the 2.6 Linux kernel, swap files are just as fast as swap partitions. Now, many admins (both Windows and Linux/UNIX) follow an old rule of thumb that your swap partition should be twice the size of your main system RAM. Let us say I’ve 32GB RAM, should I set swap space to 64 GB? Is 64 GB of swap space really required? How big should your Linux / UNIX swap space be?
The Advanced Configuration and Power Interface (ACPI) specification is an open standard operating system-centic device configuration and power management. You can easily reduce your PC’s power consumption through smart activity monitors.
With the tools and code presented, you can reduce your power consumption through a series of rules regarding application usage. After tuning your kernel, hdparm, ACPI, and CPU settings, add these application monitors to more effectively enter your low-power states.
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.
NFS is pretty old file sharing technology for UNIX based system and storage systems. However, it suffers from performance issues. NFSv4.1 address data access issues by adding a new feature called parallel NFS (pNFS) – a method of introducing Data Access Parallelism. The end result is ultra fast file sharing for clusters and high availability configurations.
The Network File System (NFS) is a stalwart component of most modern local area networks (LANs). But NFS is inadequate for the demanding input- and output-intensive applications commonly found in high-performance computing — or, at least it was. The newest revision of the NFS standard includes Parallel NFS (pNFS), a parallelized implementation of file sharing that multiplies transfer rates by orders of magnitude.
Interesting read and claim has been independently verified by somebody from Microsoft.
Greg Kroah-Hartman is a longtime developer of the Linux kernel, known for his work maintaining USB drivers as well as for packaging the SUSE kernel at Novell. O’Reilly Media recently interviewed Greg about his claim that the Linux kernel now supports more devices than any other operating system ever has, as well as why binary-only drivers are illegal, and how the kernel development process works.
Read full interview: How Linux Supports More Devices Than Any Other OS, Ever