This is a good question.  The guidance I had been given was between 4-8 SSDs per JBOD tray.  I’ve just found guidance that is a bit more precise.  This is what Microsoft says:

When purchasing storage for a tiered deployment, we recommend the following number of SSDs in a completely full disk enclosure of different bay capacities in order to achieve optimal performance for a diverse set of workloads:

Disk enclosure slot count Simple space 2-way mirror space 3-way mirror space
12 bay 2 4 6
24 bay 2 4 6
60 bay 4 8 12
70 bay 4 8 12

Minimum number of SSDs Recommended for Different Resiliency Settings

4 comments so far

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  1. This is great information that has been notoriously difficult to come by. In fact there is almost no communication anywhere on how best to layout a tiered storage space. Or even where to start. I ended up settling on 8 SSDs in a 24 bay DataOn JBOD in a 2-way mirrored space, and am very happy with the performance.

  2. Note – Not all SSD’s (SAS SSD’s) will work for clustered tiered storage. Check they have the correct firmware level

  3. What SAS SSD’s (make / model) do you guys use for Storage Spaces?

    Also, if we’ve got 3 JBOD trays for redundancy, set up as a 2way mirror – do we “have” to use 4 SSD’s in each tray, or would we get away with 2?

    And what would be the downside of only using 2 in each JBOD?

    • We use HGST SSDs from the DataOn Storage HCL. We tried SanDisk, but they have a bad habit of shipping out of date firmware and not sharing their firmware publicly on their business products site. And I’ve also heard that they have a high failure rate.

      Having only 2 SSDs puts you into a 1 column scenario with the entire virtual disk, which greatly reduces performance.

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