> Hi, > > > We're done drafting the Media Management System > (MMS) functional > > specification > > and thought it would be nice to post for community > feedback. Consider > > it out for your > > review. Appreciate the hard work by the MMS team, > especially Paul Cheng. > > > > http://www.opensolaris.org/os/project/mms/docs/ > > Some little queries: > > Why postgres? Not that I've anything against > postgres, but I wonder > why there's a need for a database at all, let alone > that it be a particular > brand?
The IEEE 1244.1-2000 spec suggests using a relational database for the MMS data model. The advantages to using a relational database are data integrity (field, table, and relationships between objects), transactions, ability to map MMP match and report statements onto SQL queries, and its a well documented and understood technology. Basically we off loaded the MMS data model complexity onto a relation database which is well suited for the task. Postgres was chosen because of the BSD license, Solaris availability, recommended internally as a good database for C applications, and Sun has 24x7 support for it. At the time MMS was started we looked at using MySQL but the cost prevented us from using it. We also looked at using a ODBC (Open DataBase Connectivity) driver but could not find a free one at the time to embed into an appliance. Now that Sun owns MySQL we will revisit the issues in a future release. >> >> > > Why have a watcher? Watcher reads the LM and DM configuration from the MM and starts the processes. Watcher also runs on remote hosts. > Could SMF be used to make sure the > appropriate processes are running? Yes, watcher is a SMF service that makes sure the appropriate LMs and DMs are running. > > If MMS requires exclusive access to a drive, does > this really mean that > I can't simply use /dev/rmt/0 as I have > traditionally? No, you have to use the MMS handle returned by a MMP mount command: mount task["1"] type[VOLUME] volname["vol1"] report[MOUNTLOGICAL] reportmode[namevalue]; Below we are using the handle to tar up some data: # tar -cvf /var/opt/SUNWsmms/handle/western.dm1.drive1.8.1202241143-SUN031 /var/adm/messages a /var/adm/messages 2064 tape blocks > I'm guessing > not, and that all I/O requests are routed through the > MMS stack? Correct. The drives are also reserved to ensure drive sharing is through MMS. > > What would iostat -En report for the MMS drives? What is currently displayed by iostat -En. > > How does MMS interact with autoloaders that might > unload/load > tapes on their own? I am not very familiar with autoloaders. A LM that supports the autoloader would need to be written or MMS would need to support stand-alone tape drives. > > Does MMS provide a mechanism for querying barcodes? Yes. A barcode is the same as the MMS PCL (physical cartidge label). Use a MMP show command to get the PCLs for a library called MyRobot: show task['1'] match[streq(LIBRARY.'LibraryName' 'MyRobot')] reportmode[value] report[CARTRIDGE.'CartridgePCL']; -David > > Thanks, > > -- > -Peter Tribble > http://www.petertribble.co.uk/ - > http://ptribble.blogspot.com/ > _______________________________________________ > storage-discuss mailing list > [email protected] > http://mail.opensolaris.org/mailman/listinfo/storage-d > iscuss This message posted from opensolaris.org _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
