Re: Question about iSCSI / NAS / Cluster

I've received a reply from John Nielsen via freebsd-scsi ML.

"...

Hi John,

I first want to say many thanks for your reply.

On Mon, May 25, 2009 at 3:56 PM, John Nielsen <[email protected]> wrote:

> 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.


yep I had such 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)


I need to seek a Windows expert down here :)


>
> 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))


In another company I have another FreeBSD NAS exporting a NFS volume to
another FreeBSD Samba server, on wich I share some directories to Ms XP
clients. I have no iSCSI on it and it's just fine. Almost 3 years up and
running.

Avoiding iSCSI it's a nice possibility but, on this new scenario the volumes
are exported to both w2k PDC and w2k BDC. My client relies upon a very
granular permission scheme. I don't know if I can handle this without a NTFS
volume. (If I'm not wrong, we can't format a NTFS partition under FreeBSD)


>
>
> > 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 prefer not to use manual tasks.


>
> > 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.


Yes you are totally right. I just want to say I am truly grateful about your
reply because my primary doubt was about the possibility or not to "map"
multiple initiators to one target. And, where is the best place to ask a
thing and get a really valid answer? yep FreeBSD ML :)

I will try to explore your tips about MS Clustering.

Once again Thanks
Francisco Cabrita



JN

..."

On Mon, May 25, 2009 at 3:39 PM, Francisco Cabrita <
[email protected]> wrote:

> Hi,
>
> I don't know if this ML is the right place to post a question about
> NAS/iSCSI and Cluster related issue. I will write it anyway.
>
> 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?
>
> 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?
>
> I really appreciate your help. Thanks in advance
>
> Best Regards
> Francisco
>
> PS: I sent this email to freebsd-scsi ML too. No anwsers until now.
>
> -- <http://www.linkedin.com/in/franciscocabrita>
>



Any aditional tips are welcome, meanwhile thanks anyway. :)

Best regards,
Francisco Cabrita
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