Hi guys, If we run iscsiadm -m node --login command through the same IP address 4 times, only one session will be created. But if we run them in parallel, then 4 same sessions could be created. ( Here, xxx.xxx.xxx.xxx is the IP address to the IPSAN. I'm using the same IP in these 4 commands. )
# iscsiadm -m node -p xxx.xxx.xxx.xxx --login & # iscsiadm -m node -p xxx.xxx.xxx.xxx --login & # iscsiadm -m node -p xxx.xxx.xxx.xxx --login & # iscsiadm -m node -p xxx.xxx.xxx.xxx --login & Logging in to [iface: default, target: iqn. xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] (multiple) Logging in to [iface: default, target: iqn. xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] (multiple) Logging in to [iface: default, target: iqn. xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] (multiple) Logging in to [iface: default, target: iqn. xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] (multiple) Login to [iface: default, target: xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] successful. Login to [iface: default, target: xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] successful. Login to [iface: default, target: xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] successful. Login to [iface: default, target: xxx.xxx.xxx.xxx, portal: xxx.xxx.xxx.xxx] successful. # iscsiadm -m session tcp: [1] xxx.xxx.xxx.xxx (non-flash) tcp: [2] xxx.xxx.xxx.xxx (non-flash) tcp: [3] xxx.xxx.xxx.xxx (non-flash) tcp: [4] xxx.xxx.xxx.xxx (non-flash) If we check the net connection in /proc/net/nf_conntrack, they are 4 TCP connections with different src ports. And if we run logout command only once, all the 4 sessions will be destroyed. Unfortunately, service like multipathd cannot tell the difference between them. If we have 4 same sessions, 4 paths will be created connecting to the dm device. But actually they are the same paths. Referring to the code, iscsiadm command does prevent creating same session by checking /sys/class/iscsi_session/ dir. But no multi-thread protection in there. Any idea how to solve this problem ? Thanks.
