我想知道 VPS 是否是导致每 3-7 天晚上 03:00 - 04:00 发生一次崩溃的根本原因（内核错误或其他问题），或者它是托管虚拟服务器的节点（后端问题）。
详细信息：基于 KVM 的 VPS，带有 CentOS 7，xfs 托管在 VPS 提供商处，该提供商拥有后端和存储后端基础设施。
通常它会以以下方式发生，正在运行的进程立即kthreadd转为D-状态（即可不间断睡眠），然后我们会收到类似以下消息：blocked for more than 120 seconds.和高 LA：
May 21 03:08:01 vps root: root 2 0.0 0.0 0 0 ? S May18 0:00 [kthreadd] May 21 03:10:01 vps root: root 2 0.0 0.0 0 0 ? S May18 0:00 [kthreadd] May 21 03:12:01 vps root: root 2 0.0 0.0 0 0 ? S May18 0:00 [kthreadd] May 21 03:14:01 vps root: root 2 0.0 0.0 0 0 ? D May18 0:00 [kthreadd] May 21 03:15:16 vps kernel: INFO: task kthreadd:2 blocked for more than 120 seconds. May 21 03:15:16 vps kernel: kthreadd D ffffffffffffffff 0 2 0 0x00000000 May 21 03:15:16 vps kernel: [<ffffffff810a65f2>] kthreadd+0x2b2/0x2f0 May 21 03:16:01 vps root: root 2 0.0 0.0 0 0 ? D May18 0:00 [kthreadd] May 21 03:18:01 vps root: root 2 0.0 0.0 0 0 ? D May18 0:00 [kthreadd] May 21 03:20:02 vps root: root 2 0.0 0.0 0 0 ? D May18 0:00 [kthreadd]
这里我们有一个调用跟踪：
May 18 04:14:37 vps kernel: INFO: task kthreadd:2 blocked for more than 120 seconds. May 18 04:14:37 vps kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. May 18 04:14:37 vps kernel: kthreadd D ffffffffffffffff 0 2 0 0x00000000 May 18 04:14:37 vps kernel: ffff88023413b4e0 0000000000000046 ffff880234120b80 ffff88023413bfd8 May 18 04:14:37 vps kernel: ffff88023413bfd8 ffff88023413bfd8 ffff880234120b80 ffff88023413b628 May 18 04:14:37 vps kernel: ffff88023413b630 7fffffffffffffff ffff880234120b80 ffffffffffffffff May 18 04:14:37 vps kernel: Call Trace: May 18 04:14:37 vps kernel: [<ffffffff8163ae49>] schedule+0x29/0x70 May 18 04:14:37 vps kernel: [<ffffffff81638b39>] schedule_timeout+0x209/0x2d0 May 18 04:14:37 vps kernel: [<ffffffff8104fac3>] ? x2apic_send_IPI_mask+0x13/0x20 May 18 04:14:37 vps kernel: [<ffffffff810b8a86>] ? try_to_wake_up+0x1b6/0x300 May 18 04:14:37 vps kernel: [<ffffffff8163b216>] wait_for_completion+0x116/0x170 May 18 04:14:37 vps kernel: [<ffffffff810b8c30>] ? wake_up_state+0x20/0x20 May 18 04:14:37 vps kernel: [<ffffffff8109e7ac>] flush_work+0xfc/0x1c0 May 18 04:14:37 vps kernel: [<ffffffff8109a7e0>] ? move_linked_works+0x90/0x90 May 18 04:14:37 vps kernel: [<ffffffffa021143a>] xlog_cil_force_lsn+0x8a/0x210 [xfs] May 18 04:14:37 vps kernel: [<ffffffffa020fa7e>] _xfs_log_force_lsn+0x6e/0x2f0 [xfs] May 18 04:14:37 vps kernel: [<ffffffff81632005>] ? __slab_free+0x10e/0x277 May 18 04:14:37 vps kernel: [<ffffffffa020fd2e>] xfs_log_force_lsn+0x2e/0x90 [xfs] May 18 04:14:37 vps kernel: [<ffffffffa0201fc9>] ? xfs_iunpin_wait+0x19/0x20 [xfs] May 18 04:14:37 vps kernel: [<ffffffffa01fe4b7>] __xfs_iunpin_wait+0xa7/0x150 [xfs] May 18 04:14:37 vps kernel: [<ffffffff810a6b60>] ? wake_atomic_t_function+0x40/0x40 May 18 04:14:37 vps kernel: [<ffffffffa0201fc9>] xfs_iunpin_wait+0x19/0x20 [xfs] May 18 04:14:37 vps kernel: [<ffffffffa01f684c>] xfs_reclaim_inode+0x8c/0x350 [xfs] May 18 04:14:37 vps kernel: [<ffffffffa01f6d77>] xfs_reclaim_inodes_ag+0x267/0x390 [xfs] May 18 04:14:37 vps kernel: [<ffffffffa01f7923>] xfs_reclaim_inodes_nr+0x33/0x40 [xfs] May 18 04:14:37 vps kernel: [<ffffffffa0206895>] xfs_fs_free_cached_objects+0x15/0x20 [xfs] May 18 04:14:37 vps kernel: [<ffffffff811e0cd8>] prune_super+0xe8/0x170 May 18 04:14:37 vps kernel: [<ffffffff8117c5c5>] shrink_slab+0x165/0x300 May 18 04:14:37 vps kernel: [<ffffffff811d5f01>] ? vmpressure+0x21/0x90 May 18 04:14:37 vps kernel: [<ffffffff8117f742>] do_try_to_free_pages+0x3c2/0x4e0 May 18 04:14:37 vps kernel: [<ffffffff8117f95c>] try_to_free_pages+0xfc/0x180 May 18 04:14:37 vps kernel: [<ffffffff8117365d>] __alloc_pages_nodemask+0x7fd/0xb90 May 18 04:14:37 vps kernel: [<ffffffff81078d73>] copy_process.part.25+0x163/0x1610 May 18 04:14:37 vps kernel: [<ffffffff810a5a20>] ? kthread_create_on_node+0x140/0x140 May 18 04:14:37 vps kernel: [<ffffffff8107a401>] do_fork+0xe1/0x320 May 18 04:14:37 vps kernel: [<ffffffff8107a666>] kernel_thread+0x26/0x30 May 18 04:14:37 vps kernel: [<ffffffff810a65f2>] kthreadd+0x2b2/0x2f0 May 18 04:14:37 vps kernel: [<ffffffff810a6340>] ? kthread_create_on_cpu+0x60/0x60 May 18 04:14:37 vps kernel: [<ffffffff81645e18>] ret_from_fork+0x58/0x90 May 18 04:14:37 vps kernel: [<ffffffff810a6340>] ? kthread_create_on_cpu+0x60/0x60
使用脏页的技巧没有帮助。
只有硬重置才能使服务器进入运行状态。
您能帮忙了解一下这是 VPS 方面还是节点方面的问题吗？
问候，亚历克斯。
答案1
这可能是备份过程，或者正在发生影响存储的事情主持人级别。这超出了您的控制范围，您应该敦促 VPS 提供商寻求解决方案。
如果他们无法解决，请考虑去其他地方。
答案2
这是因为您使用的是 Redhat/CentOS 7.2 和 xfs。内核不像 7.1 那样稳定。如果您想使用 CentOS 7.2，当前的解决方案是迁移到 ext4。