No, stopping the primary domain does not stop other domains.
alex.
On 05/12/10 11:30, Huffman, Buck wrote:
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
--
Oracle <http://www.oracle.com>
Peter Wilson | +1.650.786.0526(Office)
Oracle Systems x86 Technical Product Manager
16 Network Circle | Menlo Park, CA 94025
Green Oracle <http://www.oracle.com/commitment>
Oracle is committed to developing practices and products that help
protect the environment
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