Linux: Should You Use Twice the Amount of Ram as Swap Space?

Posted on in Categories data center, Debian Linux, fedora linux, File system, FreeBSD, Gentoo Linux, kernel, Linux, Linux desktop, Linux laptop, OpenBSD, RedHat/Fedora Linux, Solaris, Storage, Suse Linux, Tuning, Ubuntu Linux, UNIX last updated December 8, 2008

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?

MySQL Proxy Load balancing and Failover Tutorial

Posted on in Categories CentOS, Debian Linux, Download of the day, High performance computing, Howto, Linux, Monitoring, MySQL, RedHat/Fedora Linux, Suse Linux, Tuning, Ubuntu Linux, UNIX last updated August 10, 2007

MySQL Proxy is a simple and new program that sits between your client and MySQL server(s) that can monitor, analyze or transform their communication. Its flexibility allows for a wide variety of use cases, including:
a) Load balancing
b) Failover
c) Query analysis
d) Query filtering and modification
e) and many more…

MySQL Proxy tutorial

Oreilly has published a nice tutorial using MySQL proxy application:

MySQL Proxy is a lightweight binary application standing between one or more MySQL clients and a server. The clients connect to the Proxy with the usual credentials, instead of connecting to the server. The Proxy acts as man-in-the-middle between client and server.

In its basic form, the Proxy is just a redirector. It gets an empty bucket from the client (a query), takes it to the server, fills the bucket with data, and passes it back to the client.

If that were all, the Proxy would just be useless overhead. There is a little more I haven’t told you yet. The Proxy ships with an embedded Lua interpreter. Using Lua, you can define what to do with a query or a result set before the Proxy passes them along.

MySQL Proxy Load balancing and Failover Tutorial - Logo

Download MySQL proxy

You can download MySQL proxy here