Can same physical storage (user data) be accessed through two different LBAs ?

Paul Hughes phughes at solidfire.com
Thu Apr 23 19:43:35 PDT 2015


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1504242_f.htm">HTML-formatted message</a>

You need to be careful about using the term LUN when you probably mean
logical unit. It is very common for a logical unit to be accessed "through"
more than one LUN, for example when there are multiple IT nexuses, each of
which uses a unique LUN to access the same logical unit.
On Apr 23, 2015 7:53 PM, "Nadesan Narenthiran" <Nadesan.Narenthiran at hgst.com>
wrote:
>  Hi,
>
>
>
> Does SCSI explicitly prohibit accessing the same physical storage location
> through two different handles / LBAs (on drives - single LUN devices) ?
>
>
>
> The issue is really to do with access to the same user data rather than
> the actual storage location.	The question was over security whether if
> restricting access to a LBA in turn restricts access to that user data.
>
>
>
> This is an off-shoot from a conversation in another reflector.  In that
> other conversation I got educated that SCSI does not prohibit access to the
> same physical location through two different LUNs and that implementations
> exist that use this flexibility.  So I want the answer restricted within a
> single LUN.
>
> Also ignore other cases such as copy managers, replication, etc, etc, etc
> existing within this device that can copy the data over.
>
>
>
> I believe it does because the SBC model clause explains that user data is
> in a Logical Block and that a unique LBA maps to the Logical Block.  But
> there are no shalls in this explanation.  And I want to be sure all the
> explanations about physical blocks and as such do not override this.
>
>
>
> If it does prohibit such access, please point out the place(s) that
> prohibit this access.
>
>
>
> Have a nice day.
>
> Naren.
>



More information about the T10 mailing list