hello All, I know the issue is related to libvirt,but i dont know where to ask.

i have centos 6.6 running KVM as compute node in openstack icehouse when i try to attach volume to instance it shows 2596: error : virStorageFileGetMetadataRecurse:952 : Failed to open file '/dev/mapper/Mar': No such file or directory in libvirt log This does not always happen when it happens no one will be able to attach volume to instance using EMC VNX as storage backend. multipath.conf # Skip the files uner /dev that are definitely not FC/iSCSI devices # Different system may need different customization devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*" devnode "^hd[a-z][0-9]*" devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]" # Skip LUNZ device from VNX device { vendor "DGC" product "LUNZ" } } defaults { user_friendly_names no flush_on_last_del yes } devices { # Device attributed for EMC CLARiiON and VNX series ALUA device { vendor "DGC" product ".*" product_blacklist "LUNZ" path_grouping_policy group_by_prio path_selector "round-robin 0" path_checker emc_clariion features "1 queue_if_no_path" hardware_handler "1 alua" prio alua failback immediate } } Can any one help me with this issue