I'm looking in the LDOM 1.3 admin guide and it's telling me to create a vdsdev for the secondary i/o domains through the primary domain. Wouldn't this freeze the secondary domain and the multipathed guest domains if the primary goes down?
Thanks Buck From: Peter Wilson [mailto:[email protected]] Sent: Wednesday, May 12, 2010 12:40 PM To: Huffman, Buck Subject: Re: [ldoms-discuss] Question about I/O Domains Your guest domains don't need to be stopped if you reboot a primary domain, but if they are relying on IO from the primary (or other IO/Service domain), and in a single primary IO domain config, they are relying on it for disks and network devices, they will be unable to complete any IO transactions until that supporting primary/IO domain comes back and allows the transactions to complete. In the meantime the guests are 'hung' waiting for IO to complete, they can carry on using processors and memory to their hearts content but its likely that at some point they will try to do some IO and not be able to. So long as the applications in the guests can withstand the resulting very long latency IO transaction, the guest OS will continue to retry the transactions until the supporting domain comes back, at which point normal service will be resumed the transaction completes and the application moves on with its next job, not all applications can live with long latencies like this.... you can avoid this by having two or more IO/Service domains that provide seperate devices to the guest that (in the guest or to a limited extent in the LDoms framework) are configured as alternate paths for each other (Network IPMP or mirrored disks, or MPGROUP disks), hence one device the guest is trying to use may fail but the other device (from the other IO domain) is a suitable failover device and the guest can continue to operate via that device. No guest downtime, no interruption to guest service. Peter Huffman, Buck wrote: Thanks for the reply. If I have to reboot the primary domain I'm going to have to stop all the guest domains anyways, aren't I? I've read that doc and the wiki and it's telling me how to do it, not why. Buck -----Original Message----- From: Mads Toftum [mailto:[email protected]] Sent: Tuesday, May 11, 2010 4:29 PM To: Huffman, Buck Cc: [email protected]<mailto:[email protected]> Subject: Re: [ldoms-discuss] Question about I/O Domains On Tue, May 11, 2010 at 12:27:24PM -0700, Buck Huffman wrote: I'm currently testing/configuring 4 T5440's (2 prod & 2 UAT) and I have a couple of question about how I should configure my systems. I'm planning on having four guest domains running as individual cluster nodes on each system. Right now I've got a CFS share running on my primary domains to host the guest domains root file systems. I've got 4 dual-port HBA's and 3 NIC's that I need to come up with a configuration. So Question: Is there a benefit to running two I/O domains each with a NIC and an HBA that then shares to the guest domains? Or should I just run a primary that controls all the I/O? Yes, the primary benifits being redundancy and having the option to reboot control/io domains without having to shut down all guest domains. I highly recommend reading: http://wikis.sun.com/display/BluePrints/LDOMS+IO+Best+Practices+-+Data+Reliability+With+Logical+Domains vh Mads Toftum -- [cid:[email protected]]<http://www.oracle.com> Peter Wilson | +1.650.786.0526(Office) Oracle Systems x86 Technical Product Manager 16 Network Circle | Menlo Park, CA 94025 [cid:[email protected]]<http://www.oracle.com/commitment> Oracle is committed to developing practices and products that help protect the environment
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