udisks and eSATA: a question about the meaning of "detachable"

Phillip Susi psusi at cfl.rr.com
Wed Jul 13 08:49:26 PDT 2011


On 7/13/2011 10:45 AM, David Zeuthen wrote:
> First, GNOME works just fine as is - auto-mounting SATA drives will
> not buy you anything. There really is no problem here, you are making
> things up. Second, you don't appear to realize what a SAN is or how
> easy it is to connect to one either on purpose or not. Just doing e.g.

I am not making anything up; users have been filing bug reports that 
esata drives don't auto mount for years.  That is the problem.

>   # iscsiadm --mode discoverydb --type sendtargets --portal
> some-iscsi-server.corp.net --discover --login

I would think that if you attach to an iscsi drive, it is because you 
intend to actually use it.  It didn't appear by accident, like drives 
can on a SAS SAN.

Either way, that isn't an issue for adding sata to the whitelist.

> So it's very easy to do this, hell, it's a DESIRABLE feature for a
> system administrator to be able connect his local laptop (running
> GNOME) to data-center networks and connect to individual LUNs in the
> SAN. If we were to automount (or otherwise write to) every device then
> we'd be causing DATA LOSS because there is NO WAY to tell if the LUN
> is in use already.

There isn't?  I seem to remember there being a SCSI command to acquire 
exclusive access to a LUN, or it may have been even more fine grained to 
specific sector ranges.  LVM also handles the exclusivity problem for 
you.  So that just leaves the very small and rather contrived use case 
of an admin wanting to directly connect his laptop to a SAN not using 
LVM instead of going through the servers, either via NFS or iSCSI.  That 
still seems like a very small reason to maintain the whitelist but if 
you must, I still see no reason not to add sata to that list since it 
can't do SANs.



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