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 required? How big should your Linux / UNIX swap space be?
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.
Linux target framework (tgt) aims to simplify various SCSI target driver (iSCSI, Fibre Channel, SRP, etc) creation and maintenance. The key goals are the clean integration into the scsi-mid layer and implementing a great portion of tgt in user space.
The developer of IET is also helping to develop Linux SCSI target framework (stgt) which looks like it might lead to an iSCSI target implementation with an upstream kernel component. iSCSI Target can be useful:
a] To setup stateless server / client (used in diskless setups).
b] Share disks and tape drives with remote client over LAN, Wan or the Internet.
c] Setup SAN – Storage array.
d] To setup loadbalanced webcluser using cluster aware Linux file system etc.
In this tutorial you will learn how to have a fully functional Linux iSCSI SAN using tgt framework.
You can easily start / stop / pause or take a snapshot from a shell prompt under a Linux / Windows host using vmrun command. This is useful if you do not want to run web interface for starting and/or stopping VMs.
A Redundant Array of Independent Drives (or Disks), also known as Redundant Array of Inexpensive Drives (or Disks) (RAID) is an term for data storage schemes that divide and/or replicate data among multiple hard drives. RAID can be designed to provide increased data reliability or increased I/O performance, though one goal may compromise the other. There are 10 RAID level. But which one is recommended for data safety and performance considering that hard drives are commodity priced?
Wow, this is a large size desktop hard disk for storing movies, tv shows, music / mp3s, and photos. You can also load multiple operating systems using vmware or other software for testing purpose. This hard disk comes with 5 year warranty and can transfer at 300MB/s. But, How reliable is the 1.5TB hard disk?
IOzone is a filesystem benchmark tool. The benchmark generates and measures a variety of file operations. Iozone has been ported to many systems and runs under many operating systems including Windows, UNIX, Linux and BSD. This article gives you a jumpstart on performing benchmark on filesystem using iozone a free Filesystem Benchmark utility under Linux.
AdvFS is a file system that was developed by Digital Equipment Corp and continues to be part of HP’s Tru64 operating system. AdvFS has been released under GPL v2.