CentOS 7中如果使用yum命令提示如下信息，即為數據庫損壞：
error: db5 error(28) from dbenv->open: No space left on device
error: cannot open Packages index using db5 – No space left on device (28)
error: cannot open Packages database in /var/lib/rpm
CRITICAL:yum.main:
Error: rpmdb open failed
解決方法：
cd /var/lib/rpm/
mv __db* /tmp/
rm __db.* -rf
rpm –rebuilddb
yum clean all
