我在亚马逊的 AWS Lightsail 服务上有一个 VPS 服务器。我一直在使用以下两个命令测试 kdump（以触发自动内核崩溃）：
# echo 1 > /proc/sys/kernel/sysrq
# echo c > /proc/sysrq-trigger
问题是系统崩溃并重新启动，但没有保存转储。
这是我所做的检查列表：
[centos@server crash]$ systemctl status kdump
● kdump.service - Crash recovery kernel arming
Loaded: loaded (/usr/lib/systemd/system/kdump.service; enabled; vendor preset: enabled)
Active: active (exited) since Mon 2019-03-18 07:43:34 UTC; 5 days ago
Process: 4119 ExecStart=/usr/bin/kdumpctl start (code=exited, status=0/SUCCESS)
Main PID: 4119 (code=exited, status=0/SUCCESS)
CGroup: /system.slice/kdump.service
Mar 18 07:43:32 ip-.ap-northeast-1.compute.internal systemd[1]: Starting Crash recovery kernel arming...
Mar 18 07:43:34 ip-.ap-northeast-1.compute.internal kdumpctl[4119]: kexec: loaded kdump kernel
Mar 18 07:43:34 ip-.ap-northeast-1.compute.internal kdumpctl[4119]: Starting kdump: [OK]
Mar 18 07:43:34 ip-.ap-northeast-1.compute.internal systemd[1]: Started Crash recovery kernel arming.
[centos@server crash]$ dmesg | grep Reserving
[ 0.000000] Reserving 256MB of memory at 368MB for crashkernel (System RAM: 2047MB)
[centos@server crash]$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-3.10.0-957.1.3.el7.x86_64 root=UUID=f41e390f-835b-4223-a9bb-9b45984ddf8d ro console=tty0 crashkernel=256M console=ttyS0,115200
[centos@server crash]$ grep -v ^# /etc/kdump.conf
path /var/crash
core_collector makedumpfile -l --message-level 1 -d 31
default reboot
/var/log/messages 中没有崩溃日志表明可能存在任何错误。所以我想知道我可能错过了什么。或者 AWS Lightsail VPS 根本无法保存 kdump...？