[stgt] LUN missing after target server crash

Patrick H. stgt at feystorm.net
Fri Dec 10 20:51:03 CET 2010


Ok, found the problem. Its RHEL6. Since the md (raid) people decided to 
discontinue raid autodetect, redhat decided to be clever invent their 
own raid autodetect. So when the system comes up it probes all the 
devices and attempts to assemble them into a raid device, even if the 
rest of the devices in the raid group arent even there. So yes, it for 
some stupid reason builds an incomplete raid device on boot.
And whats even better is theres a kernel option to disable building md 
raid arrays. Ya, it ignores it...
So due to it being in a md device, tgtd doesnt want to add it to the 
iSCSI target

-Patrick

Sent: Fri Dec 10 2010 00:13:19 GMT-0700 (Mountain Standard Time)
From: Patrick H. <stgt at feystorm.net>
To: stgt at vger.kernel.org
Subject: LUN missing after target server crash
> I've been playing with stgt in a cluster of VMs and have run across one
> issue. Whenever the target is mounted on a client and I kill the VM
> running tgtd, when the box comes back up the LUN is missing. The target
> is still there, just the LUN is gone. If I re-add it everything works
> fine, but I would like to know why I have to do this.
> Additionally the target server has 2 targets, and both of them are in
> active sessions on a client, but its only the target that is actually
> mounted at the time that is missing after reboot.
>
> Before simulated crash
> ---------------------------
> Target 1: iqn.165.212.101.240:nas03.sdb1
>    System information:
>        Driver: iscsi
>        State: ready
>    I_T nexus information:
>        I_T nexus: 2
>            Initiator: iqn.1994-05.com.redhat:fce94bd7cd86
>            Connection: 0
>                IP Address: 165.212.101.241
>    LUN information:
>        LUN: 0
>            Type: controller
>            SCSI ID: IET     00010000
>            SCSI SN: beaf10
>            Size: 0 MB
>            Online: Yes
>            Removable media: No
>            Backing store type: rdwr
>            Backing store path: None
>        LUN: 1
>            Type: disk
>            SCSI ID: IET     00010001
>            SCSI SN: beaf11
>            Size: 268 MB
>            Online: Yes
>            Removable media: No
>            Backing store type: rdwr
>            Backing store path: /dev/sdb1
>    Account information:
>    ACL information:
>        ALL
> Target 2: iqn.165.212.101.240:nas03.sdb2
>    System information:
>        Driver: iscsi
>        State: ready
>    I_T nexus information:
>        I_T nexus: 1
>            Initiator: iqn.1994-05.com.redhat:fce94bd7cd86
>            Connection: 0
>                IP Address: 165.212.101.241
>    LUN information:
>        LUN: 0
>            Type: controller
>            SCSI ID: IET     00020000
>            SCSI SN: beaf20
>            Size: 0 MB
>            Online: Yes
>            Removable media: No
>            Backing store type: rdwr
>            Backing store path: None
>        LUN: 1
>            Type: disk
>            SCSI ID: IET     00020001
>            SCSI SN: beaf21
>            Size: 268 MB
>            Online: Yes
>            Removable media: No
>            Backing store type: rdwr
>            Backing store path: /dev/sdb2
>    Account information:
>    ACL information:
>        ALL
>
>
> After the box comes back up
> ----------------------------------
> Target 1: iqn.165.212.101.240:nas03.sdb1
>    System information:
>        Driver: iscsi
>        State: ready
>    I_T nexus information:
>        I_T nexus: 1
>            Initiator: iqn.1994-05.com.redhat:fce94bd7cd86
>            Connection: 0
>                IP Address: 165.212.101.241
>    LUN information:
>        LUN: 0
>            Type: controller
>            SCSI ID: IET     00010000
>            SCSI SN: beaf10
>            Size: 0 MB
>            Online: Yes
>            Removable media: No
>            Backing store type: rdwr
>            Backing store path: None
>    Account information:
>    ACL information:
>        ALL
> Target 2: iqn.165.212.101.240:nas03.sdb2
>    System information:
>        Driver: iscsi
>        State: ready
>    I_T nexus information:
>        I_T nexus: 2
>            Initiator: iqn.1994-05.com.redhat:fce94bd7cd86
>            Connection: 0
>                IP Address: 165.212.101.241
>    LUN information:
>        LUN: 0
>            Type: controller
>            SCSI ID: IET     00020000
>            SCSI SN: beaf20
>            Size: 0 MB
>            Online: Yes
>            Removable media: No
>            Backing store type: rdwr
>            Backing store path: None
>        LUN: 1
>            Type: disk
>            SCSI ID: IET     00020001
>            SCSI SN: beaf21
>            Size: 268 MB
>            Online: Yes
>            Removable media: No
>            Backing store type: rdwr
>            Backing store path: /dev/sdb2
>    Account information:
>    ACL information:
>        ALL
> -------------------
>
> Notice that Target 1 - LUN 1 is gone
> `tgtadm --mode logicalunit --op new --tid 1 --lun 1 -b /dev/sdb1` will
> add it back and it works fine
>
>
> My targets.conf
> --------------------
> default-driver iscsi
> iSNSServerIP 165.212.101.243
> <target iqn.165.212.101.240:nas03.sdb2>
>        backing-store /dev/sdb2
> </target>
> <target iqn.165.212.101.240:nas03.sdb1>
>        backing-store /dev/sdb1
> </target>
> --------------------
>
> Running:
> rhel6 2.6.32-71
> scsi-target-utils 1.0.4-3
>
>
>
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