Re: New server setup

David Boreham <david_list@xxxxxxxxxxx> · Thu, 14 Mar 2013 17:37:54 -0600



    On 3/14/2013 3:37 PM, Mark Kirkwood
      wrote:

    
    I
      not convinced about the need for BBU with SSD - you *can* use them without one, just
      need to make sure about suitable longevity and also the presence
      of (proven) power off protection (as discussed previously). It is
      worth noting that using unproven or SSD known to be lacking power
      off protection with a BBU will *not*
      save you from massive corruption (or device failure) upon
      unexpected power loss.
      

    I think it probably depends on the specifics of the deployment, but
    for us the fact that the BBU isn't required in order to achieve high
    write tps with SSDs is one of the key benefits -- the power, cooling
    and space savings over even a few servers are significant. In our
    case we only have one or two drives per server so no need for fancy
    drive string arrangements.

    
      Also, in terms of performance, the faster PCIe SSD do about as
      well by themselves as connected to a RAID card with BBU. In fact
      they will do better in some cases (the faster SSD can get close to
      the max IOPS many RAID cards can handle...so more than a couple of
      'em plugged into one card will be throttled by its limitations).
      

    You might want to evaluate the performance you can achieve with a
    single-SSD (use several for capacity by all means) before
    considering a RAID card + SSD solution.

    Again I bet it depends on the application but our experience with
    the older Intel 710 series is that their performance out-runs the
    CPU, at least under our PG workload.