Re: [opensuse] Write time performance - slightly out of topic



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On Tuesday, 2010-11-16 at 12:24 -0800, Greg Freemyer wrote:

On Tue, Nov 16, 2010 at 3:24 AM, Carlos E. R. <> wrote:

Carlos,

You made mention of Raid 8 earlier in this thread, which I've never heard of.

Opps! I intended to say raid 10, made of 8 disks, which is what you proposed.

I suspect you think a Raid 5 is any raid made of 5 disks.

No, never.


As to an earlier comment of yours that a Raid 1 + 0 made of 8 disks
would be slower than a Raid 0 made of 4 disks, that can be true, but
in theory the actual writing is done in parallel, so the slow down
should be negligible.

The bus would be used double time. He has to write all that data, which has to enter the system from somewhere, and perhaps treated. It is a lot of data. If redundancy is needed, better use two computers, which has the advantage of having really dual hardware. If one disk of the raid 10 fails during the process, there will be a severe hiccup till it is removed.

And on the read side, you have 2 sources for each piece of data, so in
theory you can read from a raid 1 + 0 twice as fast as from a raid 0.

Yes, but there has been no mention yet of that requirement :-)

- -- Cheers,
Carlos E. R.
(from 11.2 x86_64 "Emerald" at Telcontar)

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