前几天在惜总的“oracle运维高级群”里，BBQ 大神说了一个RHEL的bug，该bug在如下的网址中：https://access.redhat.com/solutions/433883
Red Hat Enterprise Linux 5 kernels 上是没有该问题的。
还是建议在生产环境中安装rhel6.5版本。
具体描述在下面的帖子中：
https://access.redhat.com/solutions/433883
下面全文转载：
Servers with Intel Xeon Processor E5, Intel Xeon Processor E5 v2, or Intel Xeon Processor E7 v2 and certain versions of Red Hat Enterprise Linux 6 kernels become unresponsive/hung or incur a kernel panic
Updated October 17 2014 at 1:49 AM
Issue
The server becomes unresponsive with processes blocked in the uninterruptible state ‘D’, or it incurs a kernel panic ‘hung_task: blocked tasks’. In very rare circumstances the system’s kernel can also crash/reboot due to an attempted divide-by-zero. Please see the Diagnostic Steps section for further details about possible symptoms. The issue occurs if all of the following conditions are met.
A Red Hat Enterprise Linux 6 kernel that contains this change from Red Hat private Bug 765720 is warm booted (for example, via theshutdown -r command):[sched] x86: Avoid unnecessary overflow in sched_clock
The kernel is warm booted on a machine with any of the Intel Xeon E5, Intel Xeon E5 v2, or Intel Xeon E7 v2 series processors.
The kernel is warm booted on a machine that has not been power cycled (hard reset) for a long time (typically more than ~200 days).
Notice that this does not mean that a kernel is affected if it has more than ~200 days uptime. It is the warm boot after ~200 days of ‘hardware uptime’ that actually triggers the issue. The issue occurs at a random point in time after the warm boot, typically within the range of a few minutes to a few hours.
KVM guests (on RHEL KVM hosts or RHEV-H hypervisors) that configure KVM clock as their clock source by default are not affected by the issue. For other virtualization platforms, please contact the platform vendor.
Red Hat Enterprise Linux 5 kernels that are based on upstream kernel version 2.6.18 are not affected by the issue.
Please see the Environment section for details about the versions of the Red Hat Enterprise Linux 6 kernel that are prone to the issue.
Environment
RHEL6.2 kernel versionCPU model
2.6.32-220.42.1.el6.x86_64Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
RHEL6.3 kernel versionCPU model
2.6.32-279.19.1.el6.x86_64Intel(R) Xeon(R) CPU E5-2440 0 @ 2.40GHz
2.6.32-279.22.1.el6.x86_64Intel(R) Xeon(R) CPU E5-2640 0 @ 2.50GHz
2.6.32-279.22.1.el6.x86_64Intel(R) Xeon(R) CPU E5-2630 0 @ 2.30GHz
RHEL6.4 kernel versionCPU model
2.6.32-358.el6.x86_64Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz
2.6.32-358.0.1.el6.x86_64Intel(R) Xeon(R) CPU E5-2640 0 @ 2.50GHz
2.6.32-358.6.1.el6.x86_64Intel(R) Xeon(R) CPU E5-2640 0 @ 2.50GHz
2.6.32-358.6.2.el6.x86_64Intel(R) Xeon(R) CPU E5-2650L 0 @ 1.80GHz
2.6.32-358.6.2.el6.x86_64Intel(R) Xeon(R) CPU E5-2603 0 @ 1.80GHz
2.6.32-358.15.1.el6.x86_64Intel(R) Xeon(R) CPU E5-4617 0 @ 2.90GHz
2.6.32-358.18.1.el6.x86_64Intel(R) Xeon(R) CPU E5-4617 0 @ 2.90GHz
2.6.32-358.18.1.el6.x86_64Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz
，人生就是要感受美丽的善良的，丑恶的病态的。
