I would like to know can we able to connect 2 hosts to a single T3
storage? if yes how?

Thank You.

In article <480cb9d4.0406121312.66b83cee@posting.google.com>,
 chandra_2000_us@yahoo.com (chan01) wrote:

> I would like to know can we able to connect 2 hosts to a single T3
> storage? if yes how?

Why?  Unless you use a clustering solution on both hosts, only one host 
will be able to mount the disks.  If it's for quick failover, that's 
still a clustering solution.  

AFAIK, you buy 2 HBAs and put one in each system.

-- 
DeeDee, don't press that button!  DeeDee!  NO!  Dee...

"Michael Vilain <vilain@spamcop.net>" wrote:
> In article <480cb9d4.0406121312.66b83cee@posting.google.com>,
>  chandra_2000_us@yahoo.com (chan01) wrote:
> 
> 
>>I would like to know can we able to connect 2 hosts to a single T3
>>storage? if yes how?
> Why?  Unless you use a clustering solution on both hosts, only one host 
> will be able to mount the disks.  If it's for quick failover, that's 
> still a clustering solution.  
> AFAIK, you buy 2 HBAs and put one in each system.

you can connect a single t3 brick to multiple hosts. If you
are not running a cluster (and I'm not including poor man's
cluster aka PMC) then that's fine, you just need to ensure
that you use lun masking of one sort or another to prevent
both hosts from seeing and trying to use the same lun.

make sure you get the latest controller and disk firmware
installed, and please, whatever you do, do NOT try to get
PMC going -- you'll cause yourself no end of headaches.


mcbofh

In article <40CBF2AE.7010905@optusnet.com.au>,
 McBofh <james.N0SPAm.mcpherson@optusnet.com.au> wrote:

> "Michael Vilain <vilain@spamcop.net>" wrote:
> > In article <480cb9d4.0406121312.66b83cee@posting.google.com>,
> >  chandra_2000_us@yahoo.com (chan01) wrote:
> > 
> > 
> >>I would like to know can we able to connect 2 hosts to a single T3
> >>storage? if yes how?
> > Why?  Unless you use a clustering solution on both hosts, only one host 
> > will be able to mount the disks.  If it's for quick failover, that's 
> > still a clustering solution.  
> > AFAIK, you buy 2 HBAs and put one in each system.
> 
> you can connect a single t3 brick to multiple hosts. If you
> are not running a cluster (and I'm not including poor man's
> cluster aka PMC) then that's fine, you just need to ensure
> that you use lun masking of one sort or another to prevent
> both hosts from seeing and trying to use the same lun.
> 
> make sure you get the latest controller and disk firmware
> installed, and please, whatever you do, do NOT try to get
> PMC going -- you'll cause yourself no end of headaches.

You've described essentially a mini-SAN, with different LUNs mounted on 
different hosts.  That's great that the T3 can do this.  But mounting 
the same LUN on multiple machines still needs a clustering filesystem.  
UFS won't allow it.  

My mistake for thinking that's what they wanted in the original post.  
They didn't say _why_ they wanted to connect the T3 to two systems.  My 
assumption was that they wanted to share the disks, which they didn't 
say explicitly that.

-- 
DeeDee, don't press that button!  DeeDee!  NO!  Dee...

chan01 <chandra_2000_us@yahoo.com> wrote:
> I would like to know can we able to connect 2 hosts to a single T3
> storage? if yes how?
> 

yes you can, you will need an FC switch.
 
toomas
-- 
You always have the option of pitching baseballs at empty
spray paint cans in a cul-de-sac in a Cleveland suburb.

"Michael wrote:
> You've described essentially a mini-SAN, with different LUNs mounted on 
> different hosts.  That's great that the T3 can do this.  But mounting 
> the same LUN on multiple machines still needs a clustering filesystem.  
> UFS won't allow it.  

UFS allows this but you will face data corruption unless you mount the
lun read-only from all hosts. 

But just for curiosity. What is this "custering filesystem" you are
talking about?

Sami

-- 
..signature: No such file or directory

Toomas Soome wrote:
> chan01 <chandra_2000_us@yahoo.com> wrote:
> 
>>I would like to know can we able to connect 2 hosts to a single T3
>>storage? if yes how?
>>
> 
> 
> yes you can, you will need an FC switch.
>  
> toomas

Is that a supported configuration? Our SE stated that the
T3[A-B] is only supported with a single host attachment. Sounds
like our SE is confused?

In article <dhrup1-ns2.ln1@mankeli.baana.suomi.net>,
 Sami Ketola <Sami.Ketola@iki.finland.invalid> wrote:

> "Michael wrote:
> > You've described essentially a mini-SAN, with different LUNs mounted on 
> > different hosts.  That's great that the T3 can do this.  But mounting 
> > the same LUN on multiple machines still needs a clustering filesystem.  
> > UFS won't allow it.  
> 
> UFS allows this but you will face data corruption unless you mount the
> lun read-only from all hosts. 
> 
> But just for curiosity. What is this "custering filesystem" you are
> talking about?
> 
> Sami

QFS and SUN Cluster Filesystem.  There are other filesystems besides UFS 
that coordinate access of files by locking or other means.  VMS had this 
in the 1980's.

-- 
DeeDee, don't press that button!  DeeDee!  NO!  Dee...

Sami Ketola <Sami.Ketola@iki.finland.invalid> writes:

>"Michael wrote:
>> You've described essentially a mini-SAN, with different LUNs mounted on 
>> different hosts.  That's great that the T3 can do this.  But mounting 
>> the same LUN on multiple machines still needs a clustering filesystem.  
>> UFS won't allow it.  

>UFS allows this but you will face data corruption unless you mount the
>lun read-only from all hosts. 

You will face panics *and* data corruption unless it mounted read-only
everywhere; UFS assumes that disks do not change under it so even if
there's just one writer the readers will face inconsistent data and
may produce garbage and/or panic.

Casper
-- 
Expressed in this posting are my opinions.  They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.

In article <Bf7zc.6954$aG5.631@bignews3.bellsouth.net>,
Matty  <mattyml@bellsouth.net> wrote:
>Toomas Soome wrote:
>> chan01 <chandra_2000_us@yahoo.com> wrote:
>> 
>>>I would like to know can we able to connect 2 hosts to a single T3
>>>storage? if yes how?

>> yes you can, you will need an FC switch.

>Is that a supported configuration? Our SE stated that the
>T3[A-B] is only supported with a single host attachment. Sounds
>like our SE is confused?

Well a T3 only has one host port per tray. If you need more you also
need a switch (or hub). This will not give you more than one host 
attachment, rather you attach the switch. In the case of T3a I would not 
recommend it since it doesn't support fabrics, while T3b does.

/wfr
Fredrik





-- 
Fredrik Lundholm   
dol @ ce.chalmers.se
				 

On Mon, 14 Jun 2004 08:41:23 +0000, Casper H. S. Dik wrote:

> Sami Ketola <Sami.Ketola@iki.finland.invalid> writes:
> 
>>"Michael wrote:
>>> You've described essentially a mini-SAN, with different LUNs mounted on 
>>> different hosts.  That's great that the T3 can do this.  But mounting 
>>> the same LUN on multiple machines still needs a clustering filesystem.  
>>> UFS won't allow it.  
> 
>>UFS allows this but you will face data corruption unless you mount the
>>lun read-only from all hosts. 
> 
> You will face panics *and* data corruption unless it mounted read-only
> everywhere; UFS assumes that disks do not change under it so even if
> there's just one writer the readers will face inconsistent data and
> may produce garbage and/or panic.
> 
> Casper

Well, i have a T3+ here with only one Lun, but 3 slices on it.
I mount the different slices on different workstartions.
No problem so far.

Rene

Casper H.S. Dik <Casper.Dik@sun.com> wrote:
> You will face panics *and* data corruption unless it mounted read-only
> everywhere; UFS assumes that disks do not change under it so even if
> there's just one writer the readers will face inconsistent data and
> may produce garbage and/or panic.

That's what I was talking about. You should be safe if you mount
the Shared UFS filesystem read-only everywhere.

Sami

-- 
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