Re: RAID halting

[Greg Freemyer <greg.freemyer@gmail.com>]

>> Lot of reported problems turn out to be power supplies not designed to
>> carry a Sata load.  Apparently sata drives are very demanding and many
>> "good" power supplies don't cut the mustard.
>
> Well, the server itself only has a single PATA drive as its boot drive, and
> the only peripheral card is the SATA controller.  It's a new chassis (6
> months) with a 550 Watt supply, so it's unlikely to be the culprit, even
> though the CPU is 125 Watts.  The RAID chassis is a 12 slot system with a
> 400 Watt supply and 11 drives.  I suppose I could try changing the RAID
> supply to a 600 or 700 watt model, but really 400W should be enough for 11
> drives and 3 port multipliers.  According to the spec sheets, the most power
> hungry drives in the mix (Hitachi E7K1000) require an absolute maximum of 26
> watts.  If all the drives were the same, that would be 286 watts.
> Especially given the Western Digital drives and the one Seagate (not part of
> the array) drives are specified to have somewhat lower power consumption,
> 400W should be fine.

It may or may not be as simple as you describe.

A lot of modern PSUs have multiple rails.  Each rail is independent
and provides some number of watts.

So if your CPU / graphic rail(s) are getting 300 watts out of your
550, then that only leave 250.  And that can be split among 2 or 3
rails as well.

It definitely gets complicated.

Or you may have a simple design where all the 5v lines are tied
together, same for +12v,-12v.

OTOH, if your having issues with power you should be seeing sata
transmission errors reported in the kernel log.  I don't recall your
saying, but I assume you've been watching that and nothing is showing
up during these events?

Greg
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