Hi Nicholas,
Thank you for your reply.
It seems Xen uses the SCSIID rather than the iSCSI unit serial number when repairing or mapping storage, if it changes the mapping will fail.
On the initiator side, what Xen cares about below is 36001405bff3f42a49d84cfcb64e2b933, which is used for attaching the storage LUN, I believe on other target software you can set the SCSIID that is used for each LUN but not on LIO and thus when failing LUNs between redundant nodes the SCSIID may change:
# xe sr-param-list uuid=31474fd8-7d7b-84cb-bc34-16e1105470bf
uuid ( RO) : 31474fd8-7d7b-84cb-bc34-16e1105470bf
name-label ( RW): s1-alpha-two
name-description ( RW): iSCSI SR [10.51.40.65 (iqn.2003-01.org.linux-iscsi.s1-san5.x8664:sn.cb568058d955; LUN 1: bff3f42a-49d8-4cfc-b64e-2b933e98141d: 1781.7 GB (LIO-ORG))]
host ( RO): <shared>
allowed-operations (SRO): VDI.create; VDI.snapshot; PBD.create; PBD.destroy; plug; update; VDI.destroy; scan; VDI.clone; VDI.resize; unplug
current-operations (SRO):
VDIs (SRO): f8f79b41-b0fa-4e2c-b208-6223da9facef; e6285c4a-f56a-472b-b4af-bb90dd6b94bd; e20706f4-a057-466e-9482-67c855c14eed; cc547a9e-cd10-41c5-bab7-2454b1c0498d; c062e1e0-91c8-41f3-ad8d-1611919717da; b8e2195d-58a0-49a3-8076-8ef14e2437d9; b5b98a9a-3910-4e50-adc7-b90f7804aa6a; ab0905a5-ebb1-42c0-8c8c-00448efe7cc6; a5e9a887-3932-4e5f-abe2-46e1669e11dd; 9c6933d8-cda4-4162-bc7d-e0a34c386c8a; 5235607e-da46-4bf4-9e79-40deeb6eb043; 4e76d1f6-85d8-40b0-b910-f1a0bb2bda37; 48c4fdf3-6061-4531-baf4-6516d474c7ac; 2fe1ec65-41c3-43ac-9fb9-83d54dbe2f4f; 1e31bc13-bb6a-4336-a642-b11d4a519778
PBDs (SRO): b6953525-57a2-96a1-fafb-ca85575a7a18; e7fd1d8d-e8d6-25a1-83ba-b63dc9906129; 5f8c8d0f-07cc-ec62-4d10-33cfc33ac0ae; 24a06e7f-da11-d47c-6cc6-ec34d814272e; 3e8b32fb-5596-31df-f7b6-8e421a7f0be8; 7457b26d-426c-20c0-e177-8260962ace2b; b1a0aa1f-3f06-d96f-fd0e-bfedc2d92969; 3a68f510-af9f-7d6f-17f5-c5a144902a13
virtual-allocation ( RO): 661836005376
physical-utilisation ( RO): 677900189696
physical-size ( RO): 1913080774656
type ( RO): lvmoiscsi
content-type ( RO):
shared ( RW): true
introduced-by ( RO): <not in database>
other-config (MRW):
sm-config (MRO): allocation: thick; use_vhd: true; multipathable: true; devserial: scsi-36001405bff3f42a49d84cfcb64e2b933
blobs ( RO):
local-cache-enabled ( RO): false
tags (SRW):
# sg_inq -i /dev/disk/by-scsid/36001405bff3f42a49d84cfcb64e2b933/sdm
VPD INQUIRY: Device Identification page
Designation descriptor number 1, descriptor length: 20
id_type: NAA, code_set: Binary
associated with the addressed logical unit
NAA 6, IEEE Company_id: 0x1405
Vendor Specific Identifier: 0xbff3f42a4
Vendor Specific Identifier Extension: 0x9d84cfcb64e2b933
[0x6001405bff3f42a49d84cfcb64e2b933]
Designation descriptor number 2, descriptor length: 62
id_type: T10 vendor identification, code_set: ASCII
associated with the addressed logical unit
vendor id: LIO-ORG
vendor specific: iscsi_lun_r1:bff3f42a-49d8-4cfc-b64e-2b933e98141d
Designation descriptor number 3, descriptor length: 8
transport: Internet SCSI (iSCSI)
id_type: Relative target port, code_set: Binary
associated with the target port
Relative target port: 0x1
Designation descriptor number 4, descriptor length: 8
transport: Internet SCSI (iSCSI)
id_type: Target port group, code_set: Binary
associated with the target port
Target port group: 0x0
Designation descriptor number 5, descriptor length: 8
id_type: Logical unit group, code_set: Binary
associated with the addressed logical unit
Logical unit group: 0x0
Designation descriptor number 6, descriptor length: 72
transport: Internet SCSI (iSCSI)
id_type: SCSI name string, code_set: UTF-8
associated with the target port
SCSI name string:
iqn.2003-01.org.linux-iscsi.s1-san5.x8664:sn.cb568058d955,t,0x0001
Designation descriptor number 7, descriptor length: 64
transport: Internet SCSI (iSCSI)
id_type: SCSI name string, code_set: UTF-8
associated with the target device that contains addressed lu
SCSI name string:
iqn.2003-01.org.linux-iscsi.s1-san5.x8664:sn.cb568058d955
--
Sam McLeod
From: "Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx>
Date: Monday, 30 November 2015 at 10:13 AM
To: Sam McLeod <samm@xxxxxxxxxxxxxxx>
Cc: "target-devel@xxxxxxxxxxxxxxx" <target-devel@xxxxxxxxxxxxxxx>
Subject: Re: Setting iSCSI SCSI ID with LIO?
>Hi Sam,
>
>On Mon, 2015-11-23 at 20:59 +0000, Sam McLeod wrote:
>> Hello,
>>
>> As many before me I need to set the SCSI ID for iSCSI interfaces under LIO.
>> I can do this with tgt and other legacy iSCSI targets but it seems LIO
>> doesn't have the ability to manage this?
>>
>> Setting the SCSI ID is important for iSCSI failover and iSCSI clustering to
>> ensure that initatiors can continue to connect to the target across
>> different and new hosts.
>>
>> Some initators will just use the iSCSI WWN / serial but many also need the
>> SCSI ID to remain consistant such as Xen or in our case XenServer (Citrix's
>> open source Xen product).
>>
>> There is a complecated way of maintaining SCSI ID consistancy with LIO which
>> involved enabling and managed PR with APTPL but we've found that to be
>> complex and fraught with problems when all that is require is to be able to
>> set the SCSI ID when the target is created just the same as you do the WWN
>> etc...
>>
>
>By SCSI ID, I assume you mean the SCSI Unit Serial number, that is used
>as the basis for EVPD 0x83 device identifier. (See sg_inq -i output)
>
>As mentioned in the follow-up from one of your references:
>
>http://www.spinics.net/lists/target-devel/msg02128.html
>
>and also more recently here:
>
>http://www.spinics.net/lists/target-devel/msg10494.html
>
>this value is exposed as a per device configfs attribute:
>
> /sys/kernel/config/target/core/$HBA/$DEV/wwn/vpd_unit_serial
>
>and if your performing export failover between physical nodes, you'll
>need to ensure these remain consistent for backend devices floating
>between nodes.
>
>HTH.
>
>--nab
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