iSCSI Share of ZVOL not working after EE SCALE 24.10.1 upgrade

Last week I upgraded my TrueNAS SCALE system from 24.04.2.5 to EE 24.10.1. This appears to have broken my iSCSI connection to a Rocky Linux system.

I’ve tried restarting both ends of the connection, and neither throws any errors that I can see. Running ss at both sides shows 2 open TCP connections from the Rocky Linux client to port 3260 on TrueNAS:

root@ns8:~# ss -tupn | grep 3260
tcp   ESTAB    0      0              192.168.20.254:46576          192.168.20.250:3260  users:(("iscsid",pid=1096,fd=7))
tcp   ESTAB    0      0               192.168.0.254:53686           192.168.0.250:3260  users:(("iscsid",pid=1096,fd=6))
root@ns8:~#

Running “iscsiadm -m session -P 3” at the client shows attached device:

root@ns8:~# iscsiadm -m session -P 3
iSCSI Transport Class version 2.0-870
version 6.2.1.9
Target: iqn.2005-10.org.freenas.ctl:backuppc (non-flash)
        Current Portal: 192.168.0.250:3260,1
        Persistent Portal: 192.168.0.250:3260,1
                **********
                Interface:
                **********
                Iface Name: default
                Iface Transport: tcp
                Iface Initiatorname: iqn.2005-10.org.freenas.ctl:backuppc
                Iface IPaddress: 192.168.0.254
                Iface HWaddress: default
                Iface Netdev: default
                SID: 1
                iSCSI Connection State: LOGGED IN
                iSCSI Session State: LOGGED_IN
                Internal iscsid Session State: NO CHANGE
                *********
                Timeouts:
                *********
                Recovery Timeout: 120
                Target Reset Timeout: 30
                LUN Reset Timeout: 30
                Abort Timeout: 15
                *****
                CHAP:
                *****
                username: <empty>
                password: ********
                username_in: <empty>
                password_in: ********
                ************************
                Negotiated iSCSI params:
                ************************
                HeaderDigest: None
                DataDigest: None
                MaxRecvDataSegmentLength: 262144
                MaxXmitDataSegmentLength: 1048576
                FirstBurstLength: 65536
                MaxBurstLength: 1048576
                ImmediateData: Yes
                InitialR2T: No
                MaxOutstandingR2T: 1
                ************************
                Attached SCSI devices:
                ************************
                Host Number: 2  State: running
                scsi2 Channel 00 Id 0 Lun: 0
                        Attached scsi disk sdb          State: running
        Current Portal: 192.168.20.250:3260,1
        Persistent Portal: 192.168.20.250:3260,1
                **********
                Interface:
                **********
                Iface Name: default
                Iface Transport: tcp
                Iface Initiatorname: iqn.2005-10.org.freenas.ctl:backuppc
                Iface IPaddress: 192.168.20.254
                Iface HWaddress: default
                Iface Netdev: default
                SID: 2
                iSCSI Connection State: LOGGED IN
                iSCSI Session State: LOGGED_IN
                Internal iscsid Session State: NO CHANGE
                *********
                Timeouts:
                *********
                Recovery Timeout: 120
                Target Reset Timeout: 30
                LUN Reset Timeout: 30
                Abort Timeout: 15
                *****
                CHAP:
                *****
                username: <empty>
                password: ********
                username_in: <empty>
                password_in: ********
                ************************
                Negotiated iSCSI params:
                ************************
                HeaderDigest: None
                DataDigest: None
                MaxRecvDataSegmentLength: 262144
                MaxXmitDataSegmentLength: 1048576
                FirstBurstLength: 65536
                MaxBurstLength: 1048576
                ImmediateData: Yes
                InitialR2T: No
                MaxOutstandingR2T: 1
                ************************
                Attached SCSI devices:
                ************************
                Host Number: 3  State: running
                scsi3 Channel 00 Id 0 Lun: 0
                        Attached scsi disk sdc          State: running
root@ns8:~#

But the mounted directory gives an IOERROR:

root@ns8:~# ls -l /mnt/
ls: cannot access '/mnt/backupdata': Input/output error
total 0
d????????? ? ? ? ?            ? backupdata
root@ns8:~#

Any ideas on where I should be looking next.

Cheers.