Re: Problems with scsi-target-utils when hosted on dom0 centos 7 xen box

[Nathan Coulson <nathan@xxxxxxxxxxxx>]

On 2016-04-12 09:43 AM, Nathan Coulson wrote:
> By natively, I take it using
> kernel /vmlinuz (vs kernel /xen)
>
> Not yet, but working on setting up such an environment.
>
> (At this time, I was using virt-install to reproduce the problem, and 
> the original server we are testing on did not support kvm but the 2nd 
> server does).
>
> On 2016-04-12 03:26 AM, George Dunlap wrote:
> > On Mon, Apr 11, 2016 at 9:14 PM, Nathan Coulson <nathan@xxxxxxxxxxxx> 
> > wrote:
> > > Hello
> > >
> > > We were attempting to use scsi-target-utils, hosted on a xen dom0 vm 
> > > using
> > > localhost, and running into some problems.  I was not able to 
> > > reproduce this
> > > on a centos 7.2 server using the default kernel.
> > Have you tried booting the Virt SIG kernel natively and seeing if you
> > can reproduce the problem at all?
> >
> > Thanks,
> >   -George


(Apologies for the earlier top post)

Running the kernel natively, on 3.10 or 3.18 (kernel from virt sig)
* CentOS Linux (3.18.25-19.el7.x86_64) 7 (Core))
* CentOS Linux (3.10.0-327.13.1.el7.x86_64) 7 (Core)

It works as expected with no issues.



But when booting as dom0 using the xen hypervisor
* CentOS Linux, with Xen hypervisor

tested with dom0_mem=2048M,max:2048M (as well as 1024M)

the problems occur as I have describe.



> > > (From dmesg)
> > > Apr  4 11:18:42 funk kernel: [  596.511204]  connection2:0: detected 
> > > conn
> > > error (1022)
> > > Apr  4 11:18:42 funk kernel: connection2:0: ping timeout of 5 secs 
> > > expired,
> > > recv timeout 5, last rx 4295253788, last ping 4295258790, now 
> > > 4295263808
> > > Apr  4 11:18:42 funk kernel: connection2:0: detected conn error (1022)
> > > Apr  4 11:18:42 funk iscsid: Kernel reported iSCSI connection 2:0 error
> > > (1022 - Invalid or unknown error code) state (3)
> > > Apr  4 11:18:44 funk iscsid: connection2:0 is operational after 
> > > recovery (1
> > > attempts)
> > >
> > > Repeated a few times, until eventually
> > >
> > >
> > > Apr  4 11:19:44 funk kernel: Result: hostbyte=DID_TRANSPORT_DISRUPTED
> > > driverbyte=DRIVER_OK
> > > Apr  4 11:19:44 funk kernel: sd 7:0:0:1: [sdd] CDB:
> > > Apr  4 11:19:44 funk kernel: Write(10): 2a 00 01 df c7 e8 00 00 18 00
> > > Apr  4 11:19:44 funk kernel: blk_update_request: I/O error, dev sdd, 
> > > sector
> > > 31442920
> > > Apr  4 11:19:44 funk kernel: [  658.127596] sd 7:0:0:1: [sdd]
> > > Apr  4 11:19:44 funk kernel: [  658.127688] Result:
> > > hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
> > > Apr  4 11:19:44 funk kernel: [  658.127761] sd 7:0:0:1: [sdd] CDB:
> > > Apr  4 11:19:44 funk kernel: [  658.127826] Write(10): 2a 00 01 df 
> > > c7 e8 00
> > > 00 18 00
> > > Apr  4 11:19:44 funk kernel: [  658.127927] blk_update_request: I/O 
> > > error,
> > > dev sdd, sector 31442920
> > > Apr  4 11:19:44 funk kernel: [  658.128040] sd 7:0:0:1: [sdd]
> > > Apr  4 11:19:44 funk kernel: sd 7:0:0:1: [sdd]
> > > Apr  4 11:19:44 funk kernel: [  658.128105] Result:
> > > hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
> > > Apr  4 11:19:44 funk kernel: [  658.128177] sd 7:0:0:1: [sdd] CDB:
> > > Apr  4 11:19:44 funk kernel: [  658.128241] Write(10): 2a 00 00 00 
> > > 08 00 00
> > > 00 18 00
> > > Apr  4 11:19:44 funk kernel: [  658.128339] blk_update_request: I/O 
> > > error,
> > > dev sdd, sector 2048
> > > Apr  4 11:19:44 funk kernel: Result: hostbyte=DID_TRANSPORT_DISRUPTED
> > > driverbyte=DRIVER_OK
> > > Apr  4 11:19:44 funk kernel: sd 7:0:0:1: [sdd] CDB:
> > > Apr  4 11:19:44 funk kernel: Write(10): 2a 00 00 00 08 00 00 00 18 00
> > > Apr  4 11:19:44 funk kernel: blk_update_request: I/O error, dev sdd, 
> > > sector
> > > 2048
> > >
> > >
> > > (Test Setup)
> > > scsi-target-utils installed via yum, default config
> > > /etc/tgt/conf.d/xenguests.conf
> > > <target iqn.2016-02.com.bravenet:test>
> > >      backing-store //mnt/vmdisk/test # vm image
> > > </target>
> > >
> > > systemctl tgtd restart
> > >
> > > iscsiadm -m discovery -t sendtargets -p localhost
> > >
> > > iscsiadm -m node -T iqn.2016-02.com.bravenet:test -l
> > >
> > >
> > > add it to lvm (pvcreate, vgcreate), let's call it 
> > > /dev/vmdisk.vg/test.lv
> > >
> > > and then use libvirt to attempt to install an os on 
> > > /dev/vmdisk.vg/test.lv
> > > (using anaconda)
> > >
> > >
> > >
> > >
> > > Around the time it tries to create the disk label, is when the conn 
> > > errors
> > > start, until eventually it gives up trying to create the disk label.
> > >
> > >
> > >
> > > We tested a similar setup on a centos 7.2 host we use kvm based
> > > virtualmachine hosting on (default 3.10 kernel), and it worked 
> > > fine.  It may
> > > be similar to what was reported on
> > > https://bugzilla.redhat.com/show_bug.cgi?id=1245990, but I never saw a
> > > resolution on what they discovered (other then a reference to comment18
> > > which does not appear to exist).
> > >
> > > Testing over the network appears to also work as well (where another 
> > > machine
> > > connects to scsi-target-utils on the funk server above.
> > >
> > >
> > >
> > >
> > >
> > > Longterm Purpose of the above setup, was to get direct access to a
> > > filesystem image hosted on a gluster setup, using bs-type glfs on
> > > scsi-target-utils.
> > >
> > > --
> > > Nathan Coulson
> > > www.bravenet.com
> > > nathan@xxxxxxxxxxxx
> > > _______________________________________________
> > > CentOS-virt mailing list
> > > CentOS-virt@xxxxxxxxxx
> > > https://lists.centos.org/mailman/listinfo/centos-virt
> > _______________________________________________
> > CentOS-virt mailing list
> > CentOS-virt@xxxxxxxxxx
> > https://lists.centos.org/mailman/listinfo/centos-virt


--
Nathan Coulson
www.bravenet.com
nathan@xxxxxxxxxxxx

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