Mixed SAS/SATA/SSD stack limits?

[aborzenkov]

Could someone point me to a document that clear states mixed stack limits? I know that pure SSD stack is restricted to 4 shelves, but at least one document claims 6 shelves in mixed stack (it is internal document so I'm happy to discuss it offline if appropriate). HWU shows limits for SAS/SATA/SSD separately, but again is silent about mixed usage.

I would say HWU should explicitly describe limits in this case.

[Veldmaat]

Hello and good day,

Indeed, SSD stack is restricted to 4.

SSD is in fact the highest restrictive factor in these mixtures.

Therefore, if no SSD is involved, another max value  is shown.

I will see if there is an exact document describing this.

Would you be willing the share the internal document link with me, so i can check that document for reference?

Thanking you in advance!

[aborzenkov]

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@Veldmaat wrote:

Indeed, SSD stack is restricted to 4.

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This can also be interpreted as "no more than 4 SSD shelves in a mixed stack".

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Would you be willing the share the internal document link with me, so i can check that document for reference?

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Sure. 6Gb SAS-2 SE Presentation, pages 47 which explicitly gives different limit for mixed stacks.

[shuklas]

https://track.netapp.com/Ticket.aspx?pid=2

Please pass this feedback using above link and HWU team will reach out to you .

[aborzenkov]

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@shuklas wrote:

Please pass this feedback using above link and HWU team will reach out to you .

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HWU is unclear about mixed SAS/SSD or SATA/SSD stack limits

[andris]

The Field Portal document is accurate - the hybrid stack limits were recently relaxed to maximum 6 shelves (formerly 4 shelves).  Thank you for opening the HWU ticket.

[AlexeyF]

Is there any performance penalty for the SSD Shelf if it's on the same stack as SATA(NL-SAS) shelf?

[andris]

To avoid performance impacts for the SSDs, place the SSD shelves on the ends of the (MP-HA) stack. That minimizes the number of shelf hops to the SSDs from the controllers.