On 1/15/09, Kenneth Burgener <kenneth at mail1.ttak.org> wrote: > On 1/9/2009 9:49 AM, Robert Nichols wrote: > If a hard reboot is what you are attempting to avoid, with 'kexec' even > the Linux kernel can be "reloaded" without a hardware reset. This is > convenient if you want to avoid the long system reset time. > > "Kexec is a patch to the Linux kernel that allows you to boot directly > to a new kernel from the currently running one. In the boot sequence > described above, kexec skips the entire bootloader stage (the first > part) and directly jumps into the kernel that we want to boot to. There > is no hardware reset, no firmware operation, and no bootloader involved. > The weakest link in the boot sequence -- that is, the firmware -- is > completely avoided. The big gain from this feature is that system > reboots are now extremely fast. For enterprise-class systems, kexec > drastically reduces reboot-related system downtime. For kernel and > system software developers, kexec helps you quickly reboot your system > during development or testing efforts without having to go through the > costly firmware stage every time." [1] > if you really have to have as perfect an uptime as possible then you can actually patch a running kernel using ksplice <http://www.ksplice.com/> should only be used for critical security updates but useful nonetheless mike