I hope it's okay to post a part from your syslog here:
Oct 1 11:59:21 Gen8 unassigned.devices: Disk with serial 'MSA_1040_SAN_00c0ff282747000057d6436101000000', mountpoint 'HP_MSA_1040_SAN' is not set to auto mount.
Oct 1 11:59:22 Gen8 iscsid: Connection1:0 to [target: iqn.1986-03.com.hp:storage.msa1040.1629281c75, portal: 10.99.65.226,3260] through [iface: default] is operational now
Oct 1 12:00:10 Gen8 emhttpd: MSA_1040_SAN_00c0ff282747000057d6436101000000_3600c0ff00028274757d6436101000000 (sdf) 512 64257810432
Oct 1 12:00:10 Gen8 emhttpd: read SMART /dev/sdf
From what I see iscsid is mounting the share 1 second to slow...
I mainly tested the Initiator on the Array and the Cache without a problem but now that I think about it, the Array and Cache drives are mounted way later than the Unassigned Device drives.
Would it be an option for you to actually create a Cache pool with the iSCSI disk in it?
@dlandon can you think of an easy way to delay the mount in UnassignedDevices from the disk?