iSCSI initiator and Dell PowerVault MD3000i

[Daniel Braniss]

> Daniel Braniss wrote:
> 
> [...]
> 
> > it would be helpful if you can describe what you are trying to accomplish.
> 
> To make it short:
> I am trying to connect FreeBSD 7.2 machine to storage array Dell PV MD3000i.
> MD3000i has 2 controllers to accomplish multipath fail-over in case of 
> failure of anything in the path (controller, ethernet cable, switch etc.).

> FreeBSD machine is connected by 2 NICs (bce1 and bce3), one crosslink 
> cable to controller 0, one crosslink cable to controller 1.
> As I read on the net, it seems possible to run it in this setup with 
> Windows, Linux, VMware or XenServer.
> 
> It seems not possible to use it this way on FreeBSD (with gmultipath)
> 
> Example of commands and outputs I tried is available at 
> http://pastebin.com/f2d9566c4
> 
> Links to MD3000i documentation of redundancy:
> Hardware Redundancy and Failover
> http://support.dell.com/support/edocs/systems/md3000i/en/2ndGen/HOM/HTML/using.htm#wp1091611
> 
> RAID Controller Failover Modes
> http://support.dell.com/support/edocs/systems/md3000i/en/2ndGen/HOM/HTML/using.htm#wp1093253
> 
> You can imagine my setup as the one on this page
> http://linux.dell.com/wiki/index.php/Products/HA/DellRedHatHALinuxCluster/Storage/PowerVault_MD3000i/Hardware
> Except I have just one node and no switches (directly connected)
> 
> I think there is in-band management commands (management over iSCSI 
> interface of the MD3000i) used to move virtual disks between controllers 
> driven by connected host / driver in OS.
I tend to believe that this is out-of-band, ie, http. when you connect to the
target, you get only virtual disks, ie, da0, da3, etc. this are scsi disks.
if there was some scsi-raid, then it should appear as some other device,
like tape robots, they have st0 for the tape, and ch0 for the 'robot'.
> 
> I am not too experienced with iSCSI / SCSI, so please correct me if I am 
> doing something wrong or I have wrong expectations.
> 
> Miroslav Lachman

if you are not planning to use the network, ie, you mentioned cross cable, 
and no switches, then you can get the MD3000 (notice no i :-),
and you can then connect it using SAS cable(/s) to a raid controller.
We do that here, have a dell PowerEdge 2950, running 7.2 (and soon 8.0)
conected to a MD3000. btw, SAS is several times faster than iSCSI. We run
ZFS on it and provide NAS services via NFS to several hosts.

If you go the network/iSCSI route, you can share virtual disks
aming hosts - as long as they are readlony, or move them around r/w between
hosts.

anyways, all this multipath stuff is tickling my curiosity, stay tuned :-)

danny