Delay connecting to iSCSI target on QNAP NAS

[Godrick]

4.3.3 TVS-682T

I have a number of iSCSI targets (eg, drives for backups) on my Qnap and connect to them from Windows Server iSCSI clients.

Often, even though the targets are set up to (re)connect automatically, there can be a long pause before they do so. I have no chap enabled.

What could be causing this? There are a number of options on the iSCSI target setup, not all of which are explained in the manual. Should I take care to set any of those on/off?

[storageman]

No, leave defaults.
Connection speed may vary depending on size of LUN.
Why do they need to reconnect at all?
Are servers being rebooted on a regular/daily basis?
Ideally connections should not be disconnected often.
Do want to test your network by seeing if a direct connection connects quicker than one through the network.
While it's being slow to connect, ping the ISCSI port, are you getting high latency?

[Godrick]

They need to reconnect after a reboot, such as was caused by the update to the latest qnap 4.3.3 firmware for example.

I suspect that the issue is that iscsci may be trying to reconnect with IPv6 or an incorrect IP4 address. The "portal group" seems to contain a list of addresses, including an IPv6 address, the correct one among them. The others seem to be addresses of hosts on different subsets of my lan, including subsets that are on Azure.

[storageman]

They need to reconnect after a reboot, such as was caused by the update to the latest qnap 4.3.3 firmware for example.

I suspect that the issue is that iscsci may be trying to reconnect with IPv6 or an incorrect IP4 address. The "portal group" seems to contain a list of addresses, including an IPv6 address, the correct one among them. The others seem to be addresses of hosts on different subsets of my lan, including subsets that are on Azure.

Check service binding and lock ISCSI to specific ports

[Godrick]

That's a good thought. The Qnap portal group (as reported from the Windows iSCSI initiator) seems to contain the addresses of all (real and virtual (whether in use or not)) interfaces on my Qnap.

I suspect that it's the IP6 that's the problem as the others are on different subnets, etc.