there are linux-ha lists where the folks have more clue about this than some of us, but linux software raid will allow a portion of what you are looking for. however, there have been revelations on this list as of late that indicate making a software raid set composed of other software raid sets will have problems during disk failure, due to a bug in the software. you currently also cannot run reiserfs over software raid levels 1 and above, iirc. and, ext3 is probably not ready for prime time. so no journalling with sw raid yet. attaching two controllers to same bus is possible, just make sure that neither system re-sets the bus when it powers on or loads the linux kernel code for the scsi controller. otherwise, you may not be able to re-boot a machine when the disk-pack is in use by the other. the failure mode here is not as simple as just "unmounting the disks from the primary host when it fails and then re-mounting them on the backup host" in the case that the primary host cannot unmount (crash, kernel panic, etc) cause now your raid sets are out of sync, and you wont be journalling. i hate to say it, but perhaps hardware raid with journalling via reiserfs would be better than software raid and ext2. if this setup really _requires_ dual machines, then hardware raid should not be that big of a financial stretch. if you cant justify the cost of _good_ hardware raid, then perhaps you cant justify the cost of a dual box failover system. allan Mansell Gary <[EMAIL PROTECTED]> said: > Hello all, > > I would like to set up a High Availability Linux Server running Redhat > 6.2, LVS, heartbeat etc. This machine will provide Highly Available file > storage and print services to my network of both UNIX and NT clients. The > filesystem that I want to export from the server will need to be RAID 0+1 > i.e. a mirrored stripe. > > My first question is: "What software do I need to use to create my RAID 0+1 > mirrored stripe of disks?" Also, is it possible to make it a journalled > filesystem - hence will avoiding an fsck of a huge partition and improving > data integrity. > > My second question is: "How can I share the above RAID device between two > hosts simultaneously?" My assumption is that it is possible to set the scsi > initiator to a different value for the two machines. I presume then that you > can connect the disk pack to both hosts. It is then just a case of > unmounting the disks from the primary host when it fails and then > re-mounting them on the backup host. > > Thanks in advance for any help > > > Gary Mansell > Senior Technical Analyst > IT Department > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Ricardo Consulting Engineers Ltd. Direct Line: 01273 794485 > Bridge Works, Switchboard: 01273 455611 > Shoreham By Sea, Facsimile: 01273 794111 > West Sussex. Internet: www.ricardo.com > <http://www.ricardo.com> > BN43 5FG E-mail: [EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >
