案例环境
操作系统 ：Oracle Linux Server release 5.7 64bit 虚拟机
硬件配置 : 物理机型号为DELL R720
资源配置 ：RAM 8G Intel(R) Xeon(R) CPU E5-2690 8核
案例描述
早晨发现桂林那边一台Linux服务器（虚拟机）网络无法ping通，于是联系那边的系统管理员通过Lync共享桌面给我，通过他的电脑VMware vSphere Client登录后，发现在控制台亦无响应。无法登录、无法操作，输入操作无响应。也就是说系统宕机了。没有办法，只能在虚拟机“电源”选项，通过“关闭电源”、“打开电源”选项重启Linux服务器，然后重启了Tomcat服务和Oracle数据库服务。检查了Oracle数据库的告警日志，没有发现任何错误。我的领导通过分析Linux系统日志后，发现在8月1号晚上2:22左右出现，出现内存不足，Linux出于保护机制，把一些无关紧要的进程杀掉。具体错误信息如下所示（服务器名称做了下混淆）
Aug 1 01:36:09 G*******LNX01 ntpd[3555]: kernel time sync enabled 4001
Aug 1 01:53:13 G*******LNX01 ntpd[3555]: kernel time sync enabled 0001
Aug 1 02:22:36 G*******LNX01 kernel: hald invoked oom-killer: gfp_mask=0x200da, order=0, oom_adj=0
Aug 1 02:22:37 G*******LNX01 kernel: hald cpuset=/ mems_allowed=0
Aug 1 02:22:37 G*******LNX01 kernel: Pid: 3408, comm: hald Not tainted 2.6.32-200.13.1.el5uek #1
Aug 1 02:22:37 G*******LNX01 kernel: Call Trace:
Aug 1 02:22:37 G*******LNX01 kernel: [] ? cpuset_print_task_mems_allowed+0x92/0x9e
Aug 1 02:22:37 G*******LNX01 kernel: [] oom_kill_process+0x85/0x25b
Aug 1 02:22:37 G*******LNX01 kernel: [] ? select_bad_process+0xbc/0x102
Aug 1 02:22:37 G*******LNX01 kernel: [] __out_of_memory+0x3d/0x86
Aug 1 02:22:37 G*******LNX01 kernel: [] out_of_memory+0xfc/0x195
Aug 1 02:22:37 G*******LNX01 kernel: [] __alloc_pages_nodemask+0x487/0x595
Aug 1 02:22:37 G*******LNX01 kernel: [] alloc_page_vma+0xb9/0xc8
Aug 1 02:22:37 G*******LNX01 kernel: [] read_swap_cache_async+0x52/0xf1
Aug 1 02:22:37 G*******LNX01 kernel: [] swapin_readahead+0x5d/0x9c
Aug 1 02:22:38 G*******LNX01 kernel: [] ? find_get_page+0x22/0x69
Aug 1 02:22:38 G*******LNX01 kernel: [] handle_mm_fault+0x44b/0x80f
Aug 1 02:22:40 G*******LNX01 kernel: [] ? should_resched+0xe/0x2f
Aug 1 02:22:40 G*******LNX01 kernel: [] do_page_fault+0x210/0x299
Aug 1 02:22:40 G*******LNX01 kernel: [] page_fault+0x25/0x30
Aug 1 02:22:40 G*******LNX01 kernel: Mem-Info:
Aug 1 02:22:43 G*******LNX01 kernel: Node 0 DMA per-cpu:
Aug 1 02:22:44 G*******LNX01 kernel: CPU 0: hi: 0, btch: 1 usd: 0
Aug 1 02:22:44 G*******LNX01 kernel: CPU 1: hi: 0, btch: 1 usd: 0
Aug 1 08:51:04 G*******LNX01 syslogd 1.4.1: restart.
Aug 1 08:51:04 G*******LNX01 kernel: klogd 1.4.1, log source = /proc/kmsg started.
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys cpuset
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys cpu
OOM Killer，说白了 OOM Killer 就是一层保护机制，用于避免在内存不足的时候不至于出现严重问题，把一些无关的进程优先杀掉，即在内存严重不足时，系统为了继续运转，内核会挑选一个进程，将其杀掉，以释放内存，缓解内存不足情况，不过这种保护是有限的，不能完全的保护进程的运行。
但是这个时间点是发生在凌晨2点多，于是我继续检查/var/log/messages日志信息，发现系统启动时出现了
“Phoenix BIOS detected: BIOS may corrupt low RAM, working around it”错误。于是google搜索这个错误信息。
Aug 1 08:51:04 G*******LNX01 syslogd 1.4.1: restart.
Aug 1 08:51:04 G*******LNX01 kernel: klogd 1.4.1, log source = /proc/kmsg started.
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys cpuset
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys cpu
Aug 1 08:51:04 G*******LNX01 kernel: Linux version 2.6.32-200.13.1.el5uek ([email protected]) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-50)) #1 SMP Wed Jul 27 2
1:02:33 EDT 2011
Aug 1 08:51:04 G*******LNX01 kernel: Command line: ro root=/dev/VolGroup00/LogVol00 rhgb quiet
Aug 1 08:51:04 G*******LNX01 kernel: KERNEL supported cpus:
Aug 1 08:51:04 G*******LNX01 kernel: Intel GenuineIntel
Aug 1 08:51:04 G*******LNX01 kernel: AMD AuthenticAMD
Aug 1 08:51:04 G*******LNX01 kernel: Centaur CentaurHauls
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-provided physical RAM map:
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 0000000000000000 - 000000000009f800 (usable)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000000ca000 - 00000000000cc000 (reserved)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000000dc000 - 0000000000100000 (reserved)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 0000000000100000 - 00000000bfee0000 (usable)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000bfee0000 - 00000000bfeff000 (ACPI data)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000bfeff000 - 00000000bff00000 (ACPI NVS)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000bff00000 - 00000000c0000000 (usable)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 00000000fffe0000 - 0000000100000000 (reserved)
Aug 1 08:51:04 G*******LNX01 kernel: BIOS-e820: 0000000100000000 - 0000000240000000 (usable)
Aug 1 08:51:04 G*******LNX01 kernel: DMI present.
Aug 1 08:51:04 G*******LNX01 kernel: Phoenix BIOS detected: BIOS may corrupt low RAM, working around it.
Aug 1 08:51:04 G*******LNX01 kernel: last_pfn = 0x240000 max_arch_pfn = 0x400000000
Aug 1 08:51:04 G*******LNX01 kernel: x86 PAT enabled: cpu 0, old 0x0, new 0x7010600070106
Aug 1 08:51:04 G*******LNX01 kernel: total RAM covered: 8192M
Aug 1 08:51:04 G*******LNX01 kernel: Found optimal setting for mtrr clean up
Aug 1 08:51:04 G*******LNX01 kernel: gran_size: 64K chunk_size: 64K num_reg: 4 lose cover RAM: 0G
Aug 1 08:51:04 G*******LNX01 kernel: x86 PAT enabled: cpu 0, old 0x0, new 0x7010600070106
Aug 1 08:51:04 G*******LNX01 kernel: last_pfn = 0xc0000 max_arch_pfn = 0x400000000
Aug 1 08:51:04 G*******LNX01 kernel: init_memory_mapping: 0000000000000000-00000000c0000000
Aug 1 08:51:04 G*******LNX01 kernel: init_memory_mapping: 0000000100000000-0000000240000000
Aug 1 08:51:04 G*******LNX01 kernel: RAMDISK: 37c4d000 - 37fef894
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: RSDP 00000000000f6940 00024 (v02 PTLTD )
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: XSDT 00000000bfeefddc 0005C (v01 INTEL 440BX 06040000 VMW 01324272)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: FACP 00000000bfefee98 000F4 (v04 INTEL 440BX 06040000 PTL 000F4240)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: DSDT 00000000bfef0230 0EC68 (v01 PTLTD Custom 06040000 MSFT 03000001)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: FACS 00000000bfefffc0 00040
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: BOOT 00000000bfef0208 00028 (v01 PTLTD $SBFTBL$ 06040000 LTP 00000001)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: APIC 00000000bfef0156 000B2 (v01 PTLTD ? APIC 06040000 LTP 00000000)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: MCFG 00000000bfef011a 0003C (v01 PTLTD $PCITBL$ 06040000 LTP 00000001)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: SRAT 00000000bfeefed8 00128 (v02 VMWARE MEMPLUG 06040000 VMW 00000001)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: HPET 00000000bfeefea0 00038 (v01 VMWARE VMW HPET 06040000 VMW 00000001)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: WAET 00000000bfeefe78 00028 (v01 VMWARE VMW WAET 06040000 VMW 00000001)
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 0 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 1 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 2 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 3 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 4 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 5 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 6 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: PXM 0 -> APIC 7 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: Node 0 PXM 0 0-a0000
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: Node 0 PXM 0 100000-c0000000
Aug 1 08:51:04 G*******LNX01 kernel: SRAT: Node 0 PXM 0 100000000-240000000
Aug 1 08:51:04 G*******LNX01 kernel: Bootmem setup node 0 0000000000000000-0000000240000000
Aug 1 08:51:04 G*******LNX01 kernel: NODE_DATA [000000000001b840 - 000000000003183f]
Aug 1 08:51:04 G*******LNX01 kernel: bootmap [0000000000032000 - 0000000000079fff] pages 48
Aug 1 08:51:04 G*******LNX01 kernel: (9 early reservations) ==> bootmem [0000000000 - 0240000000]
Aug 1 08:51:04 G*******LNX01 kernel: #0 [0000000000 - 0000001000] BIOS data page ==> [0000000000 - 0000001000]
Aug 1 08:51:04 G*******LNX01 kernel: #1 [0000006000 - 0000008000] TRAMPOLINE ==> [0000006000 - 0000008000]
Aug 1 08:51:04 G*******LNX01 kernel: #2 [0001000000 - 000224b73c] TEXT DATA BSS ==> [0001000000 - 000224b73c]
Aug 1 08:51:04 G*******LNX01 kernel: #3 [0037c4d000 - 0037fef894] RAMDISK ==> [0037c4d000 - 0037fef894]
Aug 1 08:51:04 G*******LNX01 kernel: #4 [000009f800 - 0000100000] BIOS reserved ==> [000009f800 - 0000100000]
Aug 1 08:51:04 G*******LNX01 kernel: #5 [000224c000 - 000224c1e8] BRK ==> [000224c000 - 000224c1e8]
Aug 1 08:51:04 G*******LNX01 kernel: #6 [0000010000 - 0000012000] PGTABLE ==> [0000010000 - 0000012000]
Aug 1 08:51:04 G*******LNX01 kernel: #7 [0000012000 - 0000017000] PGTABLE ==> [0000012000 - 0000017000]
Aug 1 08:51:04 G*******LNX01 kernel: #8 [0000017000 - 000001b840] MEMNODEMAP ==> [0000017000 - 000001b840]
Aug 1 08:51:04 G*******LNX01 kernel: found SMP MP-table at [ffff8800000f69b0] f69b0
Aug 1 08:51:04 G*******LNX01 kernel: Zone PFN ranges:
Aug 1 08:51:04 G*******LNX01 kernel: DMA 0x00000010 -> 0x00001000
Aug 1 08:51:04 G*******LNX01 kernel: DMA32 0x00001000 -> 0x00100000
Aug 1 08:51:04 G*******LNX01 kernel: Normal 0x00100000 -> 0x00240000
Aug 1 08:51:04 G*******LNX01 kernel: Movable zone start PFN for each node
Aug 1 08:51:04 G*******LNX01 kernel: early_node_map[4] active PFN ranges
Aug 1 08:51:04 G*******LNX01 kernel: 0: 0x00000010 -> 0x0000009f
Aug 1 08:51:04 G*******LNX01 kernel: 0: 0x00000100 -> 0x000bfee0
Aug 1 08:51:04 G*******LNX01 kernel: 0: 0x000bff00 -> 0x000c0000
Aug 1 08:51:04 G*******LNX01 kernel: 0: 0x00100000 -> 0x00240000
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: PM-Timer IO Port: 0x1008
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x01] lapic_id[0x01] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x03] lapic_id[0x03] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x04] lapic_id[0x04] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x05] lapic_id[0x05] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x06] lapic_id[0x06] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC (acpi_id[0x07] lapic_id[0x07] enabled)
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x00] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x01] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x02] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x03] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x04] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x05] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x06] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: LAPIC_NMI (acpi_id[0x07] high edge lint[0x1])
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: IOAPIC (id[0x08] address[0xfec00000] gsi_base[0])
Aug 1 08:51:04 G*******LNX01 kernel: IOAPIC[0]: apic_id 8, version 17, address 0xfec00000, GSI 0-23
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 high edge)
Aug 1 08:51:04 G*******LNX01 kernel: Using ACPI (MADT) for SMP configuration information
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: HPET id: 0x8086af01 base: 0xfed00000
Aug 1 08:51:04 G*******LNX01 kernel: SMP: Allowing 8 CPUs, 0 hotplug CPUs
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 000000000009f000 - 00000000000a0000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000000a0000 - 00000000000ca000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000000ca000 - 00000000000cc000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000000cc000 - 00000000000dc000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000000dc000 - 0000000000100000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000bfee0000 - 00000000bfeff000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000bfeff000 - 00000000bff00000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000c0000000 - 00000000e0000000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000e0000000 - 00000000f0000000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000f0000000 - 00000000fec00000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000fec00000 - 00000000fec10000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000fec10000 - 00000000fee00000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000fee00000 - 00000000fee01000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000fee01000 - 00000000fffe0000
Aug 1 08:51:04 G*******LNX01 kernel: PM: Registered nosave memory: 00000000fffe0000 - 0000000100000000
Aug 1 08:51:04 G*******LNX01 kernel: Allocating PCI resources starting at c0000000 (gap: c0000000:20000000)
Aug 1 08:51:04 G*******LNX01 kernel: Booting paravirtualized kernel on bare hardware
Aug 1 08:51:04 G*******LNX01 kernel: NR_CPUS:256 nr_cpumask_bits:256 nr_cpu_ids:8 nr_node_ids:1
Aug 1 08:51:04 G*******LNX01 kernel: PERCPU: Embedded 29 pages/cpu @ffff880028200000 s88280 r8192 d22312 u262144
Aug 1 08:51:04 G*******LNX01 kernel: pcpu-alloc: s88280 r8192 d22312 u262144 alloc=1*2097152
Aug 1 08:51:04 G*******LNX01 kernel: pcpu-alloc: [0] 0 1 2 3 4 5 6 7
Aug 1 08:51:04 G*******LNX01 kernel: Built 1 zonelists in Zone order, mobility grouping on. Total pages: 2064641
Aug 1 08:51:04 G*******LNX01 kernel: Policy zone: Normal
Aug 1 08:51:04 G*******LNX01 kernel: Kernel command line: ro root=/dev/VolGroup00/LogVol00 rhgb quiet
Aug 1 08:51:04 G*******LNX01 kernel: PID hash table entries: 4096 (order: 3, 32768 bytes)
Aug 1 08:51:04 G*******LNX01 kernel: Initializing CPU#0
Aug 1 08:51:04 G*******LNX01 kernel: xsave/xrstor: enabled xstate_bv 0x7, cntxt size 0x340
Aug 1 08:51:04 G*******LNX01 kernel: Checking aperture...
Aug 1 08:51:04 G*******LNX01 kernel: No AGP bridge found
Aug 1 08:51:04 G*******LNX01 kernel: PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
Aug 1 08:51:04 G*******LNX01 kernel: Placing 64MB software IO TLB between ffff880020000000 - ffff880024000000
Aug 1 08:51:04 G*******LNX01 kernel: software IO TLB at phys 0x20000000 - 0x24000000
Aug 1 08:51:04 G*******LNX01 kernel: Memory: 8183576k/9437184k available (4454k kernel code, 1049156k absent, 204452k reserved, 7191k data, 1720k init)
Aug 1 08:51:04 G*******LNX01 kernel: Hierarchical RCU implementation.
Aug 1 08:51:04 G*******LNX01 kernel: NR_IRQS:4352 nr_irqs:472
Aug 1 08:51:04 G*******LNX01 kernel: Extended CMOS year: 2000
Aug 1 08:51:04 G*******LNX01 kernel: Console: colour VGA+ 80x25
Aug 1 08:51:04 G*******LNX01 kernel: console [tty0] enabled
Aug 1 08:51:04 G*******LNX01 kernel: allocated 83886080 bytes of page_cgroup
Aug 1 08:51:04 G*******LNX01 kernel: please try 'cgroup_disable=memory' option if you don't want memory cgroups
Aug 1 08:51:04 G*******LNX01 kernel: TSC freq read from hypervisor : 2900.001 MHz
Aug 1 08:51:04 G*******LNX01 kernel: Detected 2900.001 MHz processor.
Aug 1 08:51:04 G*******LNX01 kernel: Calibrating delay loop (skipped) preset value.. 5800.00 BogoMIPS (lpj=2900001)
Aug 1 08:51:04 G*******LNX01 kernel: Security Framework initialized
Aug 1 08:51:04 G*******LNX01 kernel: SELinux: Initializing.
Aug 1 08:51:04 G*******LNX01 kernel: Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes)
Aug 1 08:51:04 G*******LNX01 kernel: Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes)
Aug 1 08:51:04 G*******LNX01 kernel: Mount-cache hash table entries: 256
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys ns
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys cpuacct
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys memory
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys devices
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys freezer
Aug 1 08:51:04 G*******LNX01 kernel: Initializing cgroup subsys net_cls
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Physical Processor ID: 0
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Processor Core ID: 0
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L1 I cache: 32K, L1 D cache: 32K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L2 cache: 256K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L3 cache: 20480K
Aug 1 08:51:04 G*******LNX01 kernel: CPU 0/0x0 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: mce: CPU supports 0 MCE banks
Aug 1 08:51:04 G*******LNX01 kernel: Performance Events: Nehalem/Corei7 events, Intel PMU driver.
Aug 1 08:51:04 G*******LNX01 kernel: ... version: 3
Aug 1 08:51:04 G*******LNX01 kernel: ... bit width: 48
Aug 1 08:51:04 G*******LNX01 kernel: ... generic registers: 4
Aug 1 08:51:04 G*******LNX01 kernel: ... value mask: 0000ffffffffffff
Aug 1 08:51:04 G*******LNX01 kernel: ... max period: 000000007fffffff
Aug 1 08:51:04 G*******LNX01 kernel: ... fixed-purpose events: 3
Aug 1 08:51:04 G*******LNX01 kernel: ... event mask: 000000070000000f
Aug 1 08:51:04 G*******LNX01 kernel: ACPI: Core revision 20090903
Aug 1 08:51:04 G*******LNX01 kernel: ftrace: converting mcount calls to 0f 1f 44 00 00
Aug 1 08:51:04 G*******LNX01 kernel: ftrace: allocating 26665 entries in 105 pages
Aug 1 08:51:04 G*******LNX01 kernel: Setting APIC routing to flat
Aug 1 08:51:04 G*******LNX01 kernel: ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
Aug 1 08:51:04 G*******LNX01 kernel: CPU0: Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz stepping 07
Aug 1 08:51:04 G*******LNX01 kernel: Booting processor 1 APIC 0x1 ip 0x6000
Aug 1 08:51:04 G*******LNX01 kernel: Initializing CPU#1
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Physical Processor ID: 0
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Processor Core ID: 1
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L1 I cache: 32K, L1 D cache: 32K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L2 cache: 256K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L3 cache: 20480K
Aug 1 08:51:04 G*******LNX01 kernel: CPU 1/0x1 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: mce: CPU supports 0 MCE banks
Aug 1 08:51:04 G*******LNX01 kernel: CPU1: Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz stepping 07
Aug 1 08:51:04 G*******LNX01 kernel: Skipping synchronization checks as TSC is reliable.
Aug 1 08:51:04 G*******LNX01 kernel: Booting processor 2 APIC 0x2 ip 0x6000
Aug 1 08:51:04 G*******LNX01 kernel: Initializing CPU#2
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Physical Processor ID: 1
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Processor Core ID: 0
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L1 I cache: 32K, L1 D cache: 32K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L2 cache: 256K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L3 cache: 20480K
Aug 1 08:51:04 G*******LNX01 kernel: CPU 2/0x2 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: mce: CPU supports 0 MCE banks
Aug 1 08:51:04 G*******LNX01 kernel: CPU2: Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz stepping 07
Aug 1 08:51:04 G*******LNX01 kernel: Booting processor 3 APIC 0x3 ip 0x6000
Aug 1 08:51:04 G*******LNX01 kernel: Initializing CPU#3
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Physical Processor ID: 1
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Processor Core ID: 1
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L1 I cache: 32K, L1 D cache: 32K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L2 cache: 256K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L3 cache: 20480K
Aug 1 08:51:04 G*******LNX01 kernel: CPU 3/0x3 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: mce: CPU supports 0 MCE banks
Aug 1 08:51:04 G*******LNX01 kernel: CPU3: Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz stepping 07
Aug 1 08:51:04 G*******LNX01 kernel: Booting processor 4 APIC 0x4 ip 0x6000
Aug 1 08:51:04 G*******LNX01 kernel: Initializing CPU#4
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Physical Processor ID: 2
Aug 1 08:51:04 G*******LNX01 kernel: CPU: Processor Core ID: 0
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L1 I cache: 32K, L1 D cache: 32K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L2 cache: 256K
Aug 1 08:51:04 G*******LNX01 kernel: CPU: L3 cache: 20480K
Aug 1 08:51:04 G*******LNX01 kernel: CPU 4/0x4 -> Node 0
Aug 1 08:51:04 G*******LNX01 kernel: mce: CPU supports 0 MCE banks
Aug 1 08:51:04 G*******LNX01 kernel: CPU4: Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz stepping 07
--More--(17%)
搜索了很多资料，等我还在茫茫大海中苦苦查证时，又连接不上该服务器，该服务器又宕机了。由于没有权限，Lync共享桌面又奇慢无比。求助于我们这边的系统管理员（拥有那边的虚拟机服务器权限），他用vSphere Client连接上去检查时，终于发现一个让人既郁闷又震惊的原因。
这台物理机DELL R720只有32G内存，上面有一个Linux系统、几个Windows系统。但是有于那边管理员添加了测试服务器，所有系统总共分配的内存加起来43G已经超过了原来物理机32G内存，导致系统间资源争用。出现内存资源不足的情况。最后Linux直接宕机的情况。
出现这种情况，一来是由于管理员疏忽，没有注意到实际内存资源分配情况。二来我不知情，信息不足（由于权限问题，我并不了解那边物理机与虚拟机的情况），一直运行的好好的系统，突然出现这个问题，导致我局限在数据库、应用程序、操作系统层面去查找原因。而没有纵览全局，从架构、资源层面去查找问题。导致一直没有查找到根本原因之所在。
解决方案
关闭测试服务器，释放出足够的内存资源。问题解决。然后系统从8月1号运行到现在再也没有出现过这个问题。
参考资料：
http://dbanotes.net/database/linux_outofmemory_oom_killer.html
http://www.huomo.cn/os/article-16bb4.html