[CentOS] iSCSI disk preperation

Mon Feb 7 20:41:37 UTC 2011
Jason Brown <jason.brown at millbrookprinting.com>

On 02/07/2011 03:26 PM, Ross Walker wrote:
> On Mon, Feb 7, 2011 at 1:56 PM, Jason Brown
> <jason.brown at millbrookprinting.com> wrote:
>> I am currently going through the process of installing/configuring an
>> iSCSI target and cannot find a good write up on how to prepare the disks
>> on the server.  I would like to mirror the two disks and present them to
>> the client.  Mirroring isn't the question, its how I go about it is the
>> problem.  When I partitioned the two drives and mirrored them together,
>> then presented them to the client, it showed to the client as a disk out
>> no partion on it.  Should I partition the drive again and then lay the
>> file system down on top of that?  Or should I delete the partitions on
>> the target server and just have sda and sdb mirrored, then when the
>> client attaches the disk, then partion it (/dev/sdc1) and write the file
>> system.
> Whatever you export, the whole disk, partition or logical volume, the
> initiator will see as a whole disk.
> So if you mirror sdaX and sdbX and export md0 the initiator will see a
> disk the size and contents of sdaX/sdbX.
> Just create the filesystem on the disk on the initiator and use it there.
> REMEMBER: iSCSI isn't a way for multiple initiators to share the same
> disk (though they can using specialized clustering file systems), it
> is a way for multiple initiators to share the same disk subsystem.
> You can't access the file system from both the target-side and
> initiator-side at once or it will corrupt the file system. If that's
> what you want then you want NFS or Samba and not iSCSI.
> -Ross
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Well my first question would be, do you really need to partition the
disks on the target or can you just RAID them together (ie sdb/sdc and
not sdb1/sdc1)?  Then create your md0 based off of the two drives.  Once
that is done, export the md0 in /etc/tgt/targets.conf to present to the

Second question.  This does not need to be a clustered file system as
only one server will need access to it at a time however, if server A
failed, could you create a new server and present it to server B and the
new server would have access to the files or would it show as an
unpartitioned drive?