Running OracleVM server 3.4.3 with guest Oracle Linux 7.3.
When running for example 'dd if=/dev/mapper/asm-vote01 of=/dev/null' together with 'dd if=/dev/mapper/asm-fra01 of=/dev/null' the %util in iostat rises to 100% on several disks, including the root partition. System will become unhandleable.
asm-vote01 and asm-fra01 are udev symlink rules.
When starting Oracle database 12.2 all ASM disks are read at the same time and the same issues occurs. Issue suddenly occured, no change were made to the config.