Re: [gentoo-server] iSCSI on Linux

[Bryn Hughes]

Doesn't look like I've had any bites out there so I'll share my 
findings at least for any future googlers...

The good news is iSCSI on Linux works.  I have been able to export 
block devices from one Linux machine and mount them on another.  
Apparently the Windows drivers are well tested too but I don't have any 
Windows machines to test with.  The initiator sees the exported iSCSI 
LUN as if it were a locally attached SCSI disk.  If you export an LVM 
volume it appears to the remote machine as a local SCSI disk and you 
can do all the usual stuff to it - i.e. you need to either create a 
partition table or use lvm on the remote machine to portion out your 
virtual device.

The bad news is the iSCSI target driver is lacking a few key functions. 
  It doesn't seem to handle resizing volumes very well - I tried 
resizing an exported LVM volume and all hell broke loose.  The biggest 
problem however is that it doesn't appear to let you make configuration 
changes without restarting the target daemon.  This is a major problem 
as it means you have to unmount _ALL_ iSCSI volumes before you can add 
a new one on the target server.  This wouldn't make for much of a SAN 
if every time you wanted to make a configuration change you had to down 
all your servers!

So here's hoping that more developers will join in on the iSCSI target 
project listed below at ardistech.com.  There's definitely something 
brewing here which will make SAN's a whole lot cheaper and easier to 
implement for the average environment.  Give it some more development 
time and it will actually be viable!

Bryn


On Apr 15, 2004, at 6:48 PM, Bryn Hughes wrote:

> I'm looking for experiences implementing iSCSI on Linux - not just as
> an initiator but as a target as well.  I've found these two projects:
>
> This is the iSCSI initiator project started by Cisco
> http://sourceforge.net/projects/linux-iscsi
>
> This is the ardistech iSCSI target project
> http://www.ardistech.com/iscsi/
>
> In theory it is possible to create iSCSI volumes using EVMS or similar
> and then mount them as block devices over ethernet to another host
> (could be Windows, Novell, Linux, OS X, whatever).  Basically you can
> build yourself a SAN using free software and normal ethernet
> (obviously gigabit preferred).
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