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Home -> Community -> Mailing Lists -> Oracle-L -> Re: SAN and ORACLE
We (Miracle A/S) have a lot of experience with Shark's. They might be
slow, but on the other hand that's countered by their high price...
The old Shark usually consists of a bunch of 7.500 RPM disks (slow, bad) in eigth-packs where one disk is a hot spare, another is a parity disk, and then six disks capable of doing all of 50 IOPS. Only choice is RAID-4 (well, they call it RAID-5) or JBOD. Even when IBM discounts this stuff 90% they still make money on it. That's because the disks are old and cheap ones. You pay a fortune for the whole 8-9 layers of stuff between the OS and the disk.
The new Shark still operates with 8-packs, but here we're at least talking 15K RPM disks, which moves the capacity to about 600 IOPS per pack. They can be configured as RAID-1+0 (the right one), but it's difficult, and people usually end up doing the default RAID-5 stuff.
Then comes the trick: They'll try to sell you a mirror of the RAID-5 configuration, thereby maximising the number of disks as much as possible:
Compare all this with the price of just having a RAID-10 attached directly to your computer, and some astonishing numbers will usually come out.
This is not specific for IBM. All SAN vendors have tricks like these, and all this nonsense can be sold by sales people to non-technical decision makers because the dream of the self-cleaning garage is compelling to most (this is true - I've talked to customers that described the wonders of a SAN as a self-cleaning garage: Throw anything in there, and it'll end up nicely stacked on the right shelf).
You might be forced to use RAID-Five/Four/Free, but no matter what: Read James Morle's paper "Sane SAN".
Mogens
ed lewis wrote:
>Hi,
> I'm interested in people's experiences with
>SAN, specifically SHARK, and Oracle.
> I have adopted a system where all of the Oracle files,
>including archive, redo, rbs etc, reside on the same
>"logical" device. I know that the placement of this data
>is handled by the SAN.
> My concern is with the recovery issue, more than
>with performance. I would like to separate the data from
>the Oracle files that are required for recovery (archive,redo,rbs,etc).
>I was hoping to create a separate "logical" device which has
>it's own physical devices that are separate from the data, and
>place the recovery files there.
> I was told that this is not possible with a SAN.
>Is this really the case ? thanks for your input.
>
> ed
>
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-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Sat Feb 07 2004 - 04:53:22 CST
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