RELENG_7: zfs mirror causes ata timeout

Daniel Eriksson daniel_k_eriksson at
Tue Jan 8 16:17:01 PST 2008

Stephen M. Rumble wrote:

> The only interesting bit of evidence I could find is that when these  
> errors do occur, smartctl reports an increase in the 
> Start_Stop_Count  
> field on ad6. ad4, which appears to work fine, doesn't demonstrate  
> this and has a much lower value.

This looks a lot like the drive momentarily shutting down due to a power
outage/dip, only to immediately start again.

Are you sure the power supplies you've tested are good and powerful
enough to power your box?

Have you tried replacing the SATA power cables (as well as the actual
data cables)? Are you using the SATA power connectors that shipped with
the PSU or a Y-cable with a molex plug? Molex<->molex connections are
notoriously unreliable (either the plug breaks allowing one of the
connecting cables to halfway slip out, or the connection is simply not
electrically sound due to bad tolerances).

/Daniel Eriksson

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