RE: iSCSI: response to second login (with same ISID)

["Lakshmi Ramasubramanian" <nramas@windows.microsoft.com>]

Even if the target is capable of supporting multiple initiators, won't
it cause problems
with devices such as disk - say, filesystem from the two initiators'
side attempt to write 
to the same sectors (even not intentionally) would cause data
corruption. Is iSCSI layer
suppose to guard against this type of device sharing? 

But, if the target serializes access to the device by reserve\release,
it would avoid
conflict. Is that how it's suppose to work? 

Thanks!
 -lakshmi

-----Original Message-----
From: Santosh Rao [mailto:santoshr@cup.hp.com] 
Sent: Friday, May 25, 2001 6:09 PM
To: Lakshmi Ramasubramanian
Cc: ips@ece.cmu.edu
Subject: Re: iSCSI: response to second login (with same ISID)



Why would the target want to reject the login, unless it is not capable
of [or does not wish to] speak to multiple initiators ?

In the case of most targets, they should be capable of handling multiple
initiators and therefore, should accept the login.

If the target is incapable of supporting multiple initiators or does not
wish to allow multiple initiators (ex : iSCSI tape drive preventing
concurrent access), then, it can reject the login with a status
class/response of 0x0205. (Target Conflict).

- Santosh


Lakshmi Ramasubramanian wrote:
> 
> How is a target driver suppose to respond to a login from an 
> initiator, when another initiator already has a session going on with 
> the given target? Is the target
> suppose to reject the second login (say, with an error "device busy"
or
> something simialar)?