[CentOS] [OT/HW] hardware raid -- comment/experience with 3Ware

[Keith Keller]

On 2013-03-06, Gordon Messmer <yinyang at eburg.com> wrote:
> On 03/06/2013 10:56 AM, Keith Keller wrote:
>> The other standard warnings about using these controllers apply (e.g.,
>> if using the write cache, have a BBU on the card
>
> A 3ware card will not enable write caching unless a BBU is present.

My man page for tw_cli implies that you can turn on write caching
without a BBU:

Please Note: 1) The default of the unit creation sets write cache
to "on" for performance reasons.  However, if there is no BBU
available for the controller, a warning is sent to standard error.

Perhaps newer controllers will refuse to enable the write cache anyway;
the tw_cli man page is written not to be specific to a particular
controller.

Since we're already offtopic, I asked around about 3ware vs. MegaRAID.
The ''consensus'' (1 < n < 5) was that MegaRAIDs had better performance
but the CLI was daunting compared to the 3ware controllers.  But if LSI
starts phasing out the 3ware line perhaps it makes sense for people to
start looking at MegaRAID controllers to be prepared for this
possibility.  (The minimal web searching I've done seems to support the
dauntiness of the MegaRAID tools.)

--keith

-- 
kkeller at wombat.san-francisco.ca.us