Question about iSCSI

[John Nielsen]

On Monday 25 May 2009 09:30:40 am Francisco Cabrita wrote:
> info:
> I have built a NAS server under FreeBSD. Geom RAID5 over 3 hard disks
> and iSCSI target0 created.
> It is up and running without problems "exporting" a SCSI driver to a Ms
> Windows 2000 Server with Microsoft iSCSI Inititator driver.
> The volume is NTFS.
>
> doubt:
> I have read multiple "old" posts around the web that I can't connect
> multiple initiators (w2k clients) to the same target. Is this true
> nowadays?

You do not want two machines to have write access to the same SCSI device 
at the same time unless you use a filesystem designed for such access. 
NTFS is not such a filesystem. Just hooking two win2k boxes to the same 
iSCSI target to do NTFS will cause problems.

Alternatives:
Microsoft clustering (two or more nodes coordinate to provide certain 
services, the disk volume is only active on one of them at any given 
time)
Some real clustered filesystem designed for shared access. I don't know of 
any for Windows off the top of my head but I haven't ever looked in to 
it.
Use the setup you have already with one w2k client, then use Windows 
filesharing to export the volume to other clients.
Avoid the middleman, drop iSCSI and just use Samba on the NAS box. (Or NFS 
if you want to dabble in Microsoft's Services for Unix... (cue scary 
music))

> Facts:
> I really need at least two w2k clients to the same "storage NAS". Any
> tip about how to solve this?
> Maybe some kind of failover technique between both w2k servers?

This is similar to the MS clustering option, there may be more manual ways 
to achieve the same effect.

> I really appreciate your help. Thanks in advance
> PS: I am thinking about sending this email to FreeBSD Cluster ML too.

Note that if you want to stick with iSCSI on the FreeBSD side then your 
questions are really Microsoft-centered, so non-FreeBSD resources may be 
more appropriate. Questions about configuring your FreeBSD storage box to 
allow concurrent access by multiple clients that happen to be running 
Windows would be appropriate on the FreeBSD-questions mailing list.

JN