Oracle Linux has recently added the Ksplice
utility to Oracle Linux, a tool that allows zero-downtime OS
upgrades without rebooting the server.
Using Ksplice, the Linux distro can be patched or
upgraded while Linux is running. Ksplice works by allowing the
systems administrator to install and deploy a Oracle Linux upgrade
without effecting the existing Linux kernel.
To apply a zero-downtime Linux upgrade using
Ksplice, the following steps occur:
Ksplice temporarily suspends all running
tasks, taking sole possession of the Linux kernel.
Ksplice then inspects all in-flight processes
and checks to ensure that the suspended processes will not be
effected by the upgrade or patch.
Ksplice then installs and links the new OS
Ksplice modifies tall suspended processes to
point then to the newly installed system functions, orphaning
the existing system function.
With the function pointers changed, Ksplice
then changes all RAM heaps and data structures (DESECTS).
Ksplice finishes by resuming all suspended
tasks to their respective processors and removes the old kernel
As we can see, Ksplice does not require a system
re-boot, but there will be a brief ?burp? is response time because
of the frozen processes.
Hence, we know that Ksplice will run faster on an
idle system than a busy system, and large SMP server with 32 and 64
CPU's will take longer than uni-processor servers.
This feature, in conjunction
transportable tablespace upgrades
and with zero-downtime upgrades using Oracle RAC, is part of
Oracle's commitment to a zero-downtime environment with no loss of
See these details on the new
Oracle Linux Ksplice
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