Do I need SAS drives?..

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Do I need SAS drives?..

Mikhail T.-4
My server has 8 "hot-plug" slots, that can accept both SATA and SAS drives. SATA ones tend to be cheaper for the same features (like cache-sizes), what am I getting for the extra money spent on SAS?

Asking specifically about the protocol differences... It would seem, for example, SATA can not be as easily hot-plugged, but with camcontrol(8) that should not be a problem, right? What else? Thank you!
--
Sent from mobile device, please, pardon shorthand.


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Sent from mobile device, please, pardon shorthand.
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Re: Do I need SAS drives?..

Ben RUBSON
> On 09 Aug 2017, at 17:59, Alan Somers <[hidden email]> wrote:
>
> 3) SAS drives have a lot of fancy features that you may not need or
> care about.  For example, (...) their error
> reporting capabilities are more sophisticated than SMART

Really interesting answer Alan, thank  you very much !
Slightly off-topic but I take this opportunity,
how do you check SAS drives health ?
I personally cron a background long test every 2 weeks (using smartmontools).
I did not experience SAS drive error yet, so not sure how this behaves.
Does the drive reports to FreeBSD when its read or write error rate cross
a threshold (so that we can replace it before it fails) ?
Or perhaps smartd will do ?

As an example below a SAS error counter log returned by smartctl :
    Errors Corrected by          Total   Correction    Gigabytes    Total
        ECC         rereads/    errors   algorithm     processed    uncorrected
    fast | delayed  rewrites  corrected  invocations  [10^9 bytes]  errors
read:   0       49        0        49     233662     73743.588           0
write:  0        3        0         3      83996      9118.895           0
verify: 0        0        0         0      28712         0.000           0

Thank you !

Ben

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