Red Hat 4, 5 take a very long time to boot and iostat output incorrect

Very slow boots or inaccurate iostat output, such as CPU utilization as high as 200% or boot times exceeding two hours, generally occur on x86 or x86_64 systems. This may result from a mismatch between the local timer (LOC) and the overall global timer for each CPU. Normally, they differ by no more than 1%. To check, use cat to read /proc/interrupts, as shown:

[root@Ezylinux ~]# cat /proc/interrupts
           CPU0           CPU1       CPU2       CPU3
  0: 1491834732(A)      0(B)          0          0    IO-APIC-edge  timer
  1:          3                0          0          0    IO-APIC-edge  i8042
  8:          1                0          0          0    IO-APIC-edge  rtc
  9:          0                0          0          0   IO-APIC-level  acpi
 12:          4                0          0          0    IO-APIC-edge  i8042
                :
                :
 82: 1364986583           0            0          0         PCI-MSI  eth0
169:   13159051        59894890    1639030          0   IO-APIC-level  megasas
NMI:     642011         564910     656217     672338
LOC: 1491834473(C)  1491834401 1491834329 1491834256
ERR:          0
MIS:          0

(A) + (B) = 1491834732
ปกติแล้ว (A)+(B) ควรที่จะมีค่าแตกต่างจาก (C) ไม่เกิน 1%

English reading note: Normally, (A) + (B) should differ from (C) by no more than 1%.

There is no fix for this issue in RHEL 4. A fix for RHEL 5 is being worked on. Thanks to RedHat.com for the information.