I'm not really aware of what the limits are - and this isn't an SR which we do 
any scalability tests on.  I would imagine it should cope with that number of 
SRs though, particularly because they are not within a pool.

If you do use pools, make sure the SRs are local rather than pool-shared so the 
number doesn't grow with the size of the pool as well.

Bob

________________________________
From: Rushikesh Jadhav [[email protected]]
Sent: 15 August 2013 18:47
To: Bob Ball
Cc: [email protected]
Subject: Re: [Xen-API] How to use iSCSI disk with Xenserver VM




On Thu, Aug 15, 2013 at 9:28 PM, Bob Ball 
<[email protected]<mailto:[email protected]>> wrote:

Don’t forget it – just introduce.



You might need to specify more parameters than you are though, and make sure 
they match up with vdi-param-list shows.

Thanks Bob,

You are right about additional parameters. They were sm-config:LUNid=0 
sm-config:SCSIid=3600144f0ffffffff0000520c011b0001.
The disk is now available in VM and is accessible from XenCenter as well.
Is there any limit per host for max number of SRs ?  25-50 SRs (VDIs) should be 
an acceptable number per host.

Since the VDI is now accessible, I would see if I can write xapi hooks on VM 
action.

Thanks once again for your help.




Bob



From: Rushikesh Jadhav 
[mailto:[email protected]<mailto:[email protected]>]
Sent: 15 August 2013 16:53

To: Bob Ball
Cc: [email protected]<mailto:[email protected]>
Subject: Re: [Xen-API] How to use iSCSI disk with Xenserver VM







On Thu, Aug 15, 2013 at 1:38 PM, Bob Ball 
<[email protected]<mailto:[email protected]>> wrote:

After running sr-introduce, find the record for the VDI on that SR and run 
vdi-introduce using the details from that record.



This will update the managed flag so XAPI knows that it can manipulate it.



Actually #xe sr-create automatically creates the VDI with managed ( RO): false 
. If I do vdi-forget and then vdi-introduce, it fails with below error



# xe vdi-introduce uuid=daff8cde-029e-2c80-d2e4-a3ff012d0342 
sr-uuid=43be7e37-ba1e-468b-4366-5c865ab4e1db 
location=daff8cde-029e-2c80-d2e4-a3ff012d0342 type=system

Error code: SR_BACKEND_FAILURE_46

Error parameters: , The VDI is not available,



May be duplicate VDI uuids ?



#xe sr-scan re-reads the disks and register it as VDI but the managed flag 
stays to "false".

The managed field is RO so I'm not able to update it.  Any ideas ?



Thanks.



Bob



From: Rushikesh Jadhav 
[mailto:[email protected]<mailto:[email protected]>]
Sent: 14 August 2013 23:40

To: Bob Ball
Cc: [email protected]<mailto:[email protected]>
Subject: Re: [Xen-API] How to use iSCSI disk with Xenserver VM







On Thu, Aug 15, 2013 at 3:15 AM, Bob Ball 
<[email protected]<mailto:[email protected]>> wrote:

I'd advise you to use sr-introduce rather than sr-create.



You'll have to provide a UUID, but you can generate one based on the targetIQN 
perhaps?



Hi Bob,



I have created the sr with type iSCSI and it has successfully created with 
vdi-per-LUN iSCSI. Then I created a VBD with

# xe vbd-create bootable=0 device=1 
vdi-uuid=daff8cde-029e-2c80-d2e4-a3ff012d0342  
vm-uuid=dc3c8f17-27bb-86e8-ee28-706ffb680dde

c0d20cbf-58a7-b2db-a4ad-85a357129e37

but Im not able to see it inside VM. When I try to activate the VBD it throws 
error like



# xe vbd-plug uuid=c0d20cbf-58a7-b2db-a4ad-85a357129e37

This operation cannot be performed because the system does not manage this VDI

vdi: c0d20cbf-58a7-b2db-a4ad-85a357129e37



# xe vbd-param-get  uuid=c0d20cbf-58a7-b2db-a4ad-85a357129e37  
param-name=attachable

false (error: Api_errors.Server_error("VDI_NOT_MANAGED", _))



Looks familiar ?





Bob



________________________________

From: Rushikesh Jadhav [[email protected]<mailto:[email protected]>]
Sent: 14 August 2013 22:42

To: Bob Ball
Cc: [email protected]<mailto:[email protected]>
Subject: Re: [Xen-API] How to use iSCSI disk with Xenserver VM







On Thu, Aug 15, 2013 at 2:57 AM, Bob Ball 
<[email protected]<mailto:[email protected]>> wrote:

Ah - understood.





Thanks.



The iSCSI SR will of course be logged in while the SR is plugged on the host 
(through the PBD).



You could potentially use a hook script (create files called vm-pre-start and 
vm-post-destroy in /etc/xapi.d) to create the SR dynamically, but beyond that 
there isn't currently a way to only have the iSCSI target logged in when the VM 
is booted.





Hopefully the sr-create will not auto format the luns on every mount :)

Thanks for your help. I'll report back if any success on this.



Bob



________________________________

From: Rushikesh Jadhav [[email protected]<mailto:[email protected]>]
Sent: 14 August 2013 22:22
To: Bob Ball
Cc: [email protected]<mailto:[email protected]>
Subject: Re: [Xen-API] How to use iSCSI disk with Xenserver VM





On Thu, Aug 15, 2013 at 2:31 AM, Bob Ball 
<[email protected]<mailto:[email protected]>> wrote:

Hi,



You can create an SR using the undocumented and unsupported "iscsi" type and 
set the device config target and targetIQN values - this will set up a single 
VDI which is a raw lun.





Thanks Bob but I'm looking for a generic way in which I would be storing the 
LUN info in VM properties other-config (MRW)  or if possible in VBD other 
config such that whenever VM tries to boot, the hook will login on iSCSI target 
and pass the device.  I think this needs be handled by blktap rather than XAPI 
or SMAPI, what you say ?



Attach that VDI to a guest and it should be what you're looking for?



Trying to automate it.





Thanks,



Bob



________________________________

From: [email protected]<mailto:[email protected]> 
[[email protected]<mailto:[email protected]>] on behalf 
of Rushikesh Jadhav [[email protected]<mailto:[email protected]>]
Sent: 14 August 2013 16:07
To: [email protected]<mailto:[email protected]>
Subject: [Xen-API] How to use iSCSI disk with Xenserver VM

Hello All,



Since normal Xen supports iSCSI lun as device for xvda, I would like to know 
its possibility with Xenserver.



What are the possible ways may be hacky to get it working ?



Since XAPI can now support Ceph as custom drive, how hard it would be to use 
same for iSCSI ?



>From Xenserver POV, I undestood that Ceph is acting as a SR but I'm expecting 
>to pass iSCSI lun as raw block device to VM.



Thanks.









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