某局点S7510E 不定时SSH无法登陆问题

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终端不定时SSH无法正常登陆设备，终端侧没有任何回显和报错，串口登录debug ssh相关无任何输出，无法正常登录时终端可以ping通带内管理地址。   

反馈的诊断信息上没有相关SSH协议的上送CPU丢包

77   IPV6_TELNET/SSH      0        0          500  S       On     SMAC 8

没有CPU的相关丢包，而debug在登陆异常时没有任何输出，正常登陆时设备可以输出相关打印，怀疑SSH报文没有正常进入设备，造成无法正常登陆

故障时抓包设备无法回应，由此可以判断设备收到了相关报文，但没有正常处理回应： 

在无法SSH登陆时，CPU有瞬时增高情况，且设备相关日志也无法打印，

通过在诊断视图（en_diag）中使用display cpu-usage task slot命令查看各进程占用CPU比例关系发现，是由于INFO进程占比过高导致CPU利用率瞬时增高INFO            77%               0/6d87c99b

Info进程为交换机在内存中写入logbuffer、或者向日志主机发送日志，又或者在FLASH中写入logfile文件所使用的进程

查看设备logbuffer中有大量dhcp的信息打印，这些打印会导致频繁读写flash，V5版本的75E和S105存在已知的频繁读写flash导致INFO进程高的已知问题

%Jul 19 11:38:07:464 2019 SZFW-HX-H3C7510 DHCPS/5/DHCPS_RECLAIM_IP: DHCP server information: Server IP = 10.18.47.1, DHCP client IP = 10.18.47.42, DHCP client hardware address = 98ee-cb23-566d, DHCP client lease = 86400.

%Jul 19 11:38:07:696 2019 SZFW-HX-H3C7510 DHCPS/5/DHCPS_ALLOCATE_IP: DHCP server information: Server IP = 10.18.47.1, DHCP client IP = 10.18.47.42, DHCP client hardware address = 98ee-cb23-566d, DHCP client lease = 86400.

%Jul 19 11:38:07:925 2019 SZFW-HX-H3C7510 DHCPS/5/DHCPS_ALLOCATE_IP: DHCP server information: Server IP = 10.18.95.1, DHCP client IP = 10.18.95.33, DHCP client hardware address = 507b-9da8-7d2d, DHCP client lease = 86400.

%Jul 19 11:38:08:154 2019 SZFW-HX-H3C7510 DHCPS/5/DHCPS_ALLOCATE_IP: DHCP server information: Server IP = 10.18.123.1, DHCP client IP = 10.18.123.60, DHCP client hardware address = 54ee-75a5-c1b0, DHCP client lease = 86400.

%Jul 19 11:38:08:390 2019 SZFW-HX-H3C7510 DHCPS/5/DHCPS_RECLAIM_IP: DHCP server information: Server IP = 10.18.47.1, DHCP client IP = 10.18.47.42, DHCP client hardware address = 98ee-cb23-566d, DHCP client lease = 86400.

可以关闭禁止logfile写入规避这个问题。

undo info-center logfile enable