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RE: Solid state disks for Oracle?

From: Kevin Closson <>
Date: Sat, 11 Mar 2006 08:31:56 -0800
Message-ID: <>


>>>Still, if you have direct attach SSD you avoid the wires and
>>>a bunch of protocol and network overhead.

SSDs are all FCP. The problem with that is if you want to have,say, 20 or so servers getting redo action on the SSD, you have to carve 20 LUNS (find me an SSD that can present its internal storage into 20 LUNS). Then you have to get the switch zoning right and then work out the front side cabling. How much simpler could the SAN gateway model be than that? You present the SSD as a single high performance LUN to the SAN gateway, put a NAS filesystem on it, export 20 directories, mount them on the respective nodes, set filesystemio_options=directIO in each init.ora, relocate the redo logs to the NFS mount and now you have <1ms redo IO for as much redo as each of the 20 servers can generate. Unless you can find me a system that is pushing more then, say, ~105MBs redo...then you'd have to configure a temed/bonded NIC for that system.

>>>power source of the SSD is not dependent on the machine, so
>>>you get the memory to the onboard disk drives in a server
>>>power outage, and if you have duplex onboard disks that is
>>>as good as raid 1.

Power? SSDs like the now defunct Imperial and others like DSI are so internally power redundant it is redicilous. Like I said early on in this thread, I'm not talking from a theoretical standpoint. I have had an 8-port MG-5000 SSD since 2001 (not cheap, not small).

>>>SSD. You preserve the utility of the SSD as long as network
>>>latency and bandwidth is sufficient for the load.

GigE is quite sufficient for transaction logging. You can see some test results here:

>>>Which is best for a given server farm will vary. Even if you
>>>use direct attach SSD, you still have to verify that the SSD
>>>is certified for the protocol it is emulating to be treated

Emulation? These devices are FCP. And who would "certify" such a thing?

Received on Sat Mar 11 2006 - 10:31:56 CST

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