Hello,
In kernel versions >= 4.16, we're intermittently seeing a ~0.3 sec delay in attaching SCSI devices (iSCSI, iSER, or SRP) to an initiator, measured from the time the iscsiadm command completes.
For example:
1. Create 4 SCSI LUNs under a wwn (we use targetcli)
2. Connect the initiator to the target LUNs:
# iscsiadm -m node -l -T <target-wwn>:ib0 -p <target-ip-addr>:3260
3. Result: Devices are attached, but maybe 25% of the time, /dev/sdb is attached 0.2-0.4 seconds after /dev/sdc, /dev/sdd, and /dev/sde.
During the delay, the output of lsscsi looks like this:
[10:0:0:0] disk LIO-ORG iser_ib0_0 4.0 - <-- unavailable /dev/sdb
[10:0:0:1] disk LIO-ORG iser_ib0_1 4.0 /dev/sdc
[10:0:0:2] disk LIO-ORG iser_ib0_2 4.0 /dev/sdd
[10:0:0:3] disk LIO-ORG iser_ib0_3 4.0 /dev/sde
The system log also reflects the delay. /dev/sdb is the first device to start setup, but it's the last to finish.
Is this behavior expected? Is there something else we need to configure?
Or is this possibly a bug introduced in 4.16?
Thanks,
Jess
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