Disk space is not a concern, performance and above all failover
capacity are more important to us. I've seen plenty of posts about
RAID 5 and RAID 10 (1 + 0)


But, the people (such as silver Dell tech support)I was asking to are
mostly suggesting me to use RAID 5, especially hardware RAID 5 with hot
spare which is not that slow compared to RAID 10, even for writing.
What do you think?


Thanks


Thomas

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On 13 Dec 2004 16:34:50 -0800, "thomaslally" <juste_ciel@hotmail.com>
wrote:

>Disk space is not a concern, performance and above all failover
>capacity are more important to us. I've seen plenty of posts about
>RAID 5 and RAID 10 (1 + 0)
>
>
>But, the people (such as silver Dell tech support)I was asking to are
>mostly suggesting me to use RAID 5, especially hardware RAID 5 with hot
>spare which is not that slow compared to RAID 10, even for writing.
>What do you think?
>
>
>Thanks
>
>
>Thomas

Raid 1+0 is far and away more resilient than raid 5.  With true 1+0
you can lose up to half of the drives in the configuration.  Now if
you lose both drives of one of the mirrors then your screwed, but
below is an example.

Stripe0	Stripe1
1	1
2	2
3	3
4	4

8 drives in a 1+0 configuration.  You can lose any combination of
drives as long as it's not the same drive for Stripe0 and Stripe1.
But you can lose 4 drives in this config, as long as they alternate...

Highly resilient by most standards.  Also damn fast.

~F

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Faeandar,

This is an interesting post, sorry to hijack it, the chances of loosing say
both drive 1's is slim but if it does happen in a business situation then
things are going to get tricky.

I suppose it's no worse than loosing two drives in a RAID 5 array (and
loosing your parity data).

I'd be interested in your opinion ?.

Thanks, Clive.

"Faeandar" <mr_castalot@yahoo.com> wrote in message
 news:ulksr059qoruqfmj3kas4itgnnea9hq86p@
4ax.com...
> On 13 Dec 2004 16:34:50 -0800, "thomaslally" <juste_ciel@hotmail.com>
> wrote:
> 
>
> Raid 1+0 is far and away more resilient than raid 5.  With true 1+0
> you can lose up to half of the drives in the configuration.  Now if
> you lose both drives of one of the mirrors then your screwed, but
> below is an example.
>
> Stripe0 Stripe1
> 1 1
> 2 2
> 3 3
> 4 4
>
> 8 drives in a 1+0 configuration.  You can lose any combination of
> drives as long as it's not the same drive for Stripe0 and Stripe1.
> But you can lose 4 drives in this config, as long as they alternate...
>
> Highly resilient by most standards.  Also damn fast.
>
> ~F

[ Post a follow-up to this message ]

What do you think about  RAID 5 with a hot spare disk?  My primary
concern is safety, reliability.  The RAID controllers on our servers
(Dell poweredge 2800 - 2 * 3.6 Xeon - 4GB RAM - 2 * 4 140GB) are fast.
Thanks

Thomas

[ Post a follow-up to this message ]

thomaslally wrote:

> What do you think about  RAID 5 with a hot spare disk?

Any reason you cannot have RAID 10 with a hot spare available for any of the
mirror pairs?

- Andrew

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