Cannot connect shared storage to VMWare EXSi 5.5 host without formatting

Client has two ESXi 5.5 hosts. Each host has its own local storage. They also have two iSCSI servers that act as shared storage.

Host2 has both of the shared storage servers connected in Storage Adaptors and under Storage. I can see the Datastores and all works fine.

Host1 used to be able to see both shared storage servers but after a recent power blip (which caused Host1 to reboot)  it cant see the Datastore . It can connect to the iSCSI target no problem but when I try to add under Storage I can only add by format the datastore - which is not going to happen as there are VMs running off of it!!

Some screen shots:
Able to see iSCSI:
1.JPGCan see the iSCSI storage when trying to add Storage:
2.JPGForced to format it:
Anyone got any ideas?

LVL 13
Mark GalvinManaging Director / Principal ConsultantAsked:
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MikeIT ManagerCommented:
Have you tried unmounting that iSCSI target and re-mounting it?
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
At the console or remotely via SSH, can you type the following:-

esxcfg-volume -l

paste the output back here

you should get something like

~ # esxcfg-volume -l
VMFS3 UUID/label: 4cc89503-f054d0d4-2865-00221958e471/nas3-vmfs
Can mount: Yes
Can resignature: No (the volume is being actively used)
Extent name: naa.600140588e9bab7d2b7ed4b53dadc1de:1     range: 0 - 1048319 (MB)

and then type...either

esxcfg-volume -m 4cc89503-f054d0d4-2865-00221958e471


esxcfg-volume -m nas3-vmfs

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Mark GalvinManaging Director / Principal ConsultantAuthor Commented:

Came back with:
"VMFS UUID/label: 5460d9c7-82e0a7f8-8bf9-0026b94773de/FNAS
Can mount: Yes
Can resignature: No (the volume is being actively used)
Extent name: t10.FreeBSD_iSCSI_Disk______002219b66311000_________________:1    range: 0 - 3814143 (MB)"

So then ran:
"esxcfg-volume -m 5460d9c7-82e0a7f8-8bf9-0026b94773de" and result was:
"Mounting volume 5460d9c7-82e0a7f8-8bf9-0026b94773de"

Worked a treat!! Thanks for that!!

Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Excellent Result!
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