Thanks for the reply... That's pretty much what I was thinking. I wasn't sure if Linux had some sort of locking facility for shared files like VSE or MVS.
John Hanley (804) 786-7823 Linux on 390 Port <LINUX-390@VM.MARIST.EDU> wrote on 10/21/2010 02:40:40 PM: > "Edmund R. MacKenty" <ed.macke...@rocketsoftware.com> > Sent by: Linux on 390 Port <LINUX-390@VM.MARIST.EDU> > > 10/21/2010 02:40 PM > > Please respond to > Linux on 390 Port <LINUX-390@VM.MARIST.EDU> > > To > > LINUX-390@VM.MARIST.EDU > > cc > > Subject > > Re: Linux Shared DASD > > On Thursday, October 21, 2010 02:07:39 pm you wrote: > > Hello, > > I have a requirement to share (read/write) a set of files (XML) between two > > zLinux guests under the same zVM LPAR. > > The zLinux guests will run WebSphere and update the same set of files. > > Can I define an mdisk as "MWV" and allow the zLinux guests to share? > > Or would it be prudent to setup something like NFS to handle the sharing? > > I'm not sure of the frequency of updates, but I don't think it would be > > very heavy. > > Don't define the MDISKs to both be writable filesystems on each guest, because > that risks corrupting the filesystems. Use NFS instead. > > If you search the list archives you'll find discussions on this, but here's > the short explanation of why sharing read-write MDISKs between Linuxguests is > dangerous. If you mount the same filesystem read-write on two Linux guests, > both will be caching blocks from that filesystem. If one guest changes a > block, the other may not see the change because it reads from its cache > instead of the disk. If the second one then changes that block, they are > overwriting the change made by the first guest. If that block happens to > contain a directory, or part of the filesystem's hash table, you've just > trashed things badly. > > So use NFS, because there's only one Linux guest caching that filesystem. > - MacK. > ----- > Edmund R. MacKenty > Software Architect > Rocket Software > 275 Grove Street - Newton, MA 02466-2272 - USA > Tel: +1.617.614.4321 > Email: m...@rs.com > Web: www.rocketsoftware.com > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
