Increase the ZFS partition to use the entire disk

It's normal to have the partition 1/9 in ZFS. If ZFS thinks it is using a 'whole disk' then the partitions are created. This is the way non-multipath full disks should be treated.

The reason for this 8MB buffer space is to allow the use of slightly-different disk capacities in a physical setup. This isn't something you need to worry about when using the zpool online -e utility, as it rewrites the partition table during expansion.

Disk /dev/nvme0n1: 960.2 GB, 960197124096 bytes, 1875385008 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: gpt
Disk identifier: E63B403D-D140-A84B-99EB-56DEDC8B91E4


#         Start          End    Size  Type            Name
 1         2048   1875367935  894.3G  Solaris /usr &  zfs-aaba011d48bf00f6
 9   1875367936   1875384319      8M  Solaris reserve

The order should be something like:

1. Rescan your disk: something like echo 1 > /sys/block/sdb/device/rescan.
2. partprobe
3. zpool online -e poolname sdb
4. Reboot or reload ZFS module.
5. zpool list
6. Review the value of EXPANDSZ.
7. zpool online -e poolname sdb

If this sequence doesn't work, just delete partition #9 and repeat the above.