iSCSI in oVirt/RHV is broken. For years.

Reported this a while: https://bugzilla.redhat.com/show_bug.cgi?id=1474904

iSCSI Multipath in the engine does not means a thing. It’s broken.

I don’t know why the oVirt team does not acknowledge this. I’m being an idiot always answering and inquiring about this, but I can’t understand why anyone doesn’t take this seriously. It’s real, it’s affects everyone and simply does not makes sense.

Hi Shani,

thank's for the reply.

In this case, the bounding, I think, is inapropriate.

The dell compellent has 2 "fault domain" with différent IP network

This is a iSCSI array with 8 front-end ports (4 per controller). The iSCSI network is simple: two independant switches with a single VLAN, front-end ports are split equally between the two switches.

And for each serveur one Ethernet controller is connected on each switch. So, bonding seems inappropriate.

(see this dell documentation : https://downloads.dell.com/manuals/common/scv30x0iscsi-setup_en.pdf )

Maybe I misunderstood how iscsi bonding work in ovirt ?

Regards,

Sylvain

---

De: "Shani Leviim" <sleviim@redhat.com>
À: dalmasso@cines.fr
Cc: "users" <users@ovirt.org>
Envoyé: Mardi 7 Avril 2020 15:41:16
Objet: Re: [ovirt-users] Ovirt and Dell Compellent in ISCSI

Hi Sylvain,

Not sure that's exactly what you're looking for, but you can define an iscsi bond (iscsi multipath) using the UI and REST API:

https://www.ovirt.org/develop/release-management/features/storage/iscsi-multipath.html

Note that this is a character of the DC.

Hope it helps.

Regards,

Shani Leviim

On Wed, Apr 1, 2020 at 12:35 PM <dalmasso@cines.fr> wrote:

hi all,
we use ovirt 4.3 on dell server r640 runing centos 7.7 and a storage bay Dell Compellent SCv3020 in ISCSI.
We use two 10gb interfaces for iSCSI connection on each dell server.
If we configure ISCSI connection directly from web IU, we can’t specify the two physical ethernet interface , and there are missing path . (only 4 path on 8)
So, on the shell of hypervisor we use this commands  for configure the connections :
iscsiadm -m iface -I em1 --op=new # 1st ethernet interface
iscsiadm -m iface -I p3p1 --op=new # 2d ethernet interface
iscsiadm -m discovery -t sendtargets -p xx.xx.xx.xx
iscsiadm -m node -o show
iscsiadm -m node --login
after this, on the web IU we can connect our LUN with all path.

Also, I don’t understand how to configure multipath in the web UI . By defaut the configuration is in failover :
multipath -ll :
36000d3100457e4000000000000000005 dm-3 COMPELNT,Compellent Vol 
size=500G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  |- 23:0:0:1 sdb 8:16   active ready running
  |- 24:0:0:1 sdd 8:48   active ready running
  |- 25:0:0:1 sdc 8:32   active ready running
  |- 26:0:0:1 sde 8:64   active ready running
  |- 31:0:0:1 sdf 8:80   active ready running
  |- 32:0:0:1 sdg 8:96   active ready running
  |- 33:0:0:1 sdh 8:112  active ready running
  |- 34:0:0:1 sdi 8:128  active ready running

I think round robind or another configuration will be more performent.

So can we made this configuration , select physical interface and configure multipath in web UI ? for easyly maintenance and adding other server ?

Thank you.

Sylvain.
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