Re: Moving to flash storage

From: Miroslav Potocky <>
Date: Fri, 18 May 2018 14:14:11 +0200
Message-ID: <>

Ad. Advanced compression option:

Most of all-flash storage I know includes some kind of transparent compression directly on storage level so you can save on Oracle licenses there. For NetApp FAS8080 I'm certain there is storage level in-line compression available (included in base license).

As for the move to all-flash. If you are considering top-tier enterprise level stuff like NetApp FAS8080 even without any changes on DB level you should get quite some improvement and most of your IO issues will either simply disappear or shift to network/DB level (YMMV). Also, watch for any downstream standby databases _not_ on all-flash. They'll be heavily hammered once primary is on SSDs.

Miro P.

On 18.05.2018 06:08, Mladen Gogala wrote:
> On 05/17/2018 10:15 AM, Matt Adams wrote:
>> It looks like we might be migrating the big production databases (2
>> of them for a combined 40 Tb or so) to a NetApp 8080 Flash storage
>> device. These database have thousands of concurrent connections and
>> turn over between 10 G and 30 G of redo per hour.
>> I seem to vaguely recall a message or two here on the list over the
>> last couple of years regarding things to watch out for when migrating
>> to flash storage.
> Well, the characteristics of the flash storage are very different from
> the characteristics of the spinning disks. The first important
> difference is that the difference between sequential access and random
> access is much smaller. Make sure to gather new system statistics.
> Also, flash disks are much more expensive than rotational disk. So
> much so that advanced compression option suddenly starts making sense.
> The "compress for all operations" can really save you some space and
> money. Benefits of the index scan are much smaller with flash storage.
> Also, in my experience, using larger block size like 16k can make some
> difference for some kinds of flash memory. Talk to NetApp and ask them
> for their recommendations. Reading bigger blocks in bursts can speed
> things up.
> As for the transfer rates, you want 32 Gb/sec fibre channel adapters.
> It doesn't get any faster than that. RDBMS systems are usually I/O
> bound, not CPU bound. And flash is much faster variety of IO.
> --
> Mladen Gogala
> Database Consultant
> Tel: (347) 321-1217


Received on Fri May 18 2018 - 14:14:11 CEST

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