Welcome to Alibaba Cloud Elastic Compute Service ! [root@liruilong ~]# mdadm -bash: mdadm: command not found [root@liruilong ~]# [root@liruilong ~]# yum search mdadm Loaded plugins: fastestmirror Repository epel is listed more than once in the configuration Loading mirror speeds from cached hostfile * base: mirrors.cloud.aliyuncs.com * extras: mirrors.cloud.aliyuncs.com * updates: mirrors.cloud.aliyuncs.com ============================= N/S matched: mdadm ============================== mdadm.x86_64 : The mdadm program controls Linux md devices (software RAID : arrays) Name and summary matches only, use "search all" for everything. [root@liruilong ~]# yum install -y mdadm.x86_64 Loaded plugins: fastestmirror Repository epel is listed more than once in the configuration Loading mirror speeds from cached hostfile * base: mirrors.cloud.aliyuncs.com * extras: mirrors.cloud.aliyuncs.com * updates: mirrors.cloud.aliyuncs.com Resolving Dependencies --