HP 3PAR StoreServ 7400 4-node (RAW Capacity??)

[Eng.AhmedAmin]

Hi All,
I has problem with 7400-4node (QR485A):

1- The max raw capacity is 1100TB, how that??
2- I want implement 700TB usable (After Raid5 8:1) with (4TB NL + 920 GB SSD)
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I think the max capacity for 4 node with 18 enclosures is
(4TB * 18 * 24) + (1.2TB * 48)= 2304 TB
2304 * 0.93= 2143 TB it is total capacity
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I think the max raw capacity for 4 node with 18 enclosures ( Raid 5 8:1) is
(4 TB * 16 * 24) + (1.2 TB * 42) = 1586 TB
1586 * .93= 1475 TB it is total raw capacity not 1100 TB
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I think 3par for raid 5 8:1 require (MUST) that
Enclosure: (4 enclosure - 1)
HD: (9 HD -1)
now the max raw capacity are
Enclosure M6720 ( 16 - 4 ) = 12 enclosures (3.5 in)
and Enclosure M6710 with 4node ( 4 -1 )= 3 enclosure (2.5 in)

so the total is 12 enclosure (3.5) + 3 enclosure (2.5)
HD 3.5in (12 enclosure * 24 HD)= 288 HD
Raid 5 (8:1) = (256:32) = 256 HD (3.5 in)

HD 2.5in ( 3 enclosure * 24 ) = 72 HD
Raid 5 (8:1) = ( 64:8) = 64 HD (2.5in)

max raw is (256 * 4 TB) + (64 * 1.2) = 1100 TB
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This is big problem I will lost more money and more space
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IS there any software to solve this problem?
How I can Implement a storage with 700 TB (4TB NL + 920G SSD)??

Thanks & Best Regards
Ahmed Amin

[Cleanur]

Ahmed,

Without going through all the numbers, there are two very real problems with what you are trying to do.

Firstly mixing SDD & NL without an intermediate FC tier is going to make for a poor configuration unless you absolutely understand your workload. The response time differential between SSD and NL is huge so unless you can guarantee the correct data is always on SSD at the right time, then you're going to see some huge performance swings especially on net new writes. Secondly and most importantly trying to run Raid 5 on 4TB Nearline drives is an absolute recipe for disaster and the larger the stripe width the greater the potential for data loss.

The max supported capacity is related to maintaining scalable performance on the array, 3PAR isn't pushed as a cheap and deep archive tier and with it's support for thin technology multi petabyte support is not typically required in the market the 7400 plays in. If you want to work out the best configuration to meet your needs then I'd advise you contact HP directly or a HP channel partner. Both have access to free Presales support consultants who can advise you on best practice and work out a valid configuration to meet your needs.

BTW it's doable in a single 7400 using Raid 6 on NL. remember a 4TB drive in base 2 is actually closer to ~3.6TiB.

[Eng.AhmedAmin]

Dear Cleanur,
Thanks for reply,
I will buy HP 3PAR 7000 Data Optimization Software Suite v2 (BD270A) to do tiering between
NL and SSD
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I will configure SSD with 100 TB
and configure NL with 600 TB
all this after raid 5 8:1

this mean I will buy 198 * 4 TB NL with 8 enclosure
and 144 * 920 TB SSD with 6 enclosure
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About speed I has 100 TB and data will down to NL during month

so what you are see?

[Cleanur]

You'll likely be wasting you money.

As mentioned above If you use 4TB drives with Raid 5, regardless of the vendor or storage array in use, you can pretty much guarantee you will have data loss and if you're tiering, that data loss will be catastrophic. This isn't something 3PAR specific it's just a fact of life, Raid 5 can't adequately protect drives of this type. Firstly there's the much higher platter bit error rate on NL and then the potential rebuild times involved for drives of this size increases the likelihood of a second (overlap) failure.

You need to engage with someone who understands how this really works. Adaptive Optimization (SUb LUN Tiering) is not an archive solution, nor will it allow you to pin or place data based on your own criteria, such as age, last access time etc. It's designed to squeeze the best possible performance out of a minimal amount of SSD. So unless your 100TB of data is all very very hot (highly unlikely) the majority will end up on NL almost immediately and not SSD.

You can hit the same capacity point on NL with 6 more drives using Raid 6 14+2, but I'd urge you to contact a local reseller / HP resource to get this validated, otherwise it could end up being a rather expensive mistake for all involved.

http://www.zdnet.com/blog/storage/why-r ... n-2009/162

[Eng.AhmedAmin]

Dear Cleanur,
I happy for your reply
I will do Raid 6 for NL
and SSD with Raid 5

please give me your advise to implement this solution with 700 TB raw
thanks & Best Regards
Ahmed

[Cleanur]

Sorry I can't give you that advice as I don't understand your use case and trying to design a complex system via messages exchanged on a forum is not really ideal either.

As I've said contact you local Reseller / HP resource, there's no commitment required, they'll put the design and pricing together for you for free and they have the tools to help you work out the most effective combination of drives.

See here viewtopic.php?f=18&t=556&start=10

Thank you for the advice. I did meet with HP/presales and we worked through the configurators and came up with a layout

[Eng.AhmedAmin]

Thanks )