Once disk is plugged in after system reboot:
mount | grep /dev/sdb
/dev/sdb1 on /mnt/sdb1 type ext4 (rw,relatime)
/dev/sdb2 on /mnt/sdb2 type ext4 (rw,relatime)
blkid | grep /dev/sdb
/dev/sdb2: LABEL="RedNateck_NanoPi" UUID="24f1ed11-ae7f-4444-9b8e-519271058638" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="587fb637-02"
/dev/sdb1: LABEL="RedNateck_Docker" UUID="cce28d02-24e0-488e-a848-f60d0d28e7c1" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="587fb637-01"
lsusb
Bus 007 Device 001: ID 1d6b:0002 Linux 5.15.78 xhci-hcd xHCI Host Controller
Bus 002 Device 001: ID 1d6b:0002 Linux 5.15.78 ehci_hcd EHCI Host Controller
Bus 004 Device 001: ID 1d6b:0001 Linux 5.15.78 ohci_hcd Generic Platform OHCI controller
Bus 006 Device 001: ID 1d6b:0003 Linux 5.15.78 xhci-hcd xHCI Host Controller
Bus 008 Device 005: ID 152d:0578 JMicron USB3.0 External HDD
Bus 008 Device 001: ID 1d6b:0003 Linux 5.15.78 xhci-hcd xHCI Host Controller
Bus 005 Device 002: ID 058f:6387 Generic Mass Storage
Bus 001 Device 001: ID 1d6b:0002 Linux 5.15.78 ehci_hcd EHCI Host Controller
Bus 003 Device 001: ID 1d6b:0001 Linux 5.15.78 ohci_hcd Generic Platform OHCI controller
Bus 005 Device 001: ID 1d6b:0002 Linux 5.15.78 xhci-hcd xHCI Host Controller
In lsusb my SSD is Bus 008 Device 005: ID 152d:0578 JMicron USB3.0 External HDD
So everything is just fine. Now let's reboot system and all results now shows that there is no a such thing like /mnt/sdb. That's I meant by inaccessible. If I recconnect usb cable then again disk will be visible. My first thought was that during moment when disk is unavailable system doesn't know about it's existance. But as I show with command fuser -m /mnt/sdb2 it knows that there is and attached a dozens of processes.