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This is a script to clean up iSCSI multipath faulty devices.

Some iSCSI multipath faulty devices may show up due to some unexpected timeout or some operations out of synchronization. Too many faulty devices may result in high CPU consumption and affect the system performance. It is difficult for OpenStack common logic to avoid faulty devices in all corner cases. And either in VNX side or VNX Cinder Driver side, it is also impossible to completely avoid the faulty device issue under current architecture. As a workaround, this external helper script is created to clean up the iSCSI multipath faulty devices.

• This script only support iSCSI storage from VNX array.
• The usage is faulty_device_cleanup.py --config-file /etc/nova/nova.conf.
• faulty_device_cleanup.py --config-file /etc/nova/nova.conf --detection-only will only print the number of faulty devices without cleaning them up.
• Current implementation has dependency on some OpenStack-specific packages/modules (such as nova.db.sqlalchemy, nova.context, nova.utils and oslo.config) and DM Mulitpath.
• It is recommended to use flush_on_last_del yes in defaults section of /etc/multipath.conf. Otherwise map in use failure may come out during cleanup and delay the deletion of multipath faulty devices.