attached devices exported by tgt not oprational

when i export many block device by tgt , in one single target , this means many exported lun in one target, to another 
machine by iscsi。 

in another machine , attach the devices by open-iscsi。when i wait the 
size of the device attached change from 0 to correct size， i create raid1 with two devices by mdadm。at this time, mdadm report like 
"/dev/sdem is not suitable for this array.", i read the code of mdadm ,that because it cannot open the device。sometime it even report 
"failed to open /dev/** after earlier success - aborting "。

i do not know whether it's because i used the device when it's not ready yet, or the problem of tgt。

all the above said happened when many target lun(tgt) created at the same 
time concurrently。it do not happen in nomal time. when i change tgt to iet, it 
do not happen either。

 

tgt version: 1.0.48

open-iscsi version:iscsiadm version 2.0-873 

linux system: Linux  3.10.40-amd64  GNU/Linux 

 

 

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Zhiyong Xi