Message-ID: <44566426.2040707@aviawest.com>
Date: Mon, 01 May 2006 12:40:22 -0700
From: Erik Myllymaki <erik.myllymaki@aviawest.com>
Reply-To: erik.myllymaki@aviawest.com
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To: Scott Marlowe <smarlowe@g2switchworks.com>
CC: Tom Arthurs <tarthurs@jobflash.com>, Mark Lewis <mark.lewis@mir3.com>,
	Vivek Khera <vivek@khera.org>,
	Pgsql performance <pgsql-performance@postgresql.org>
Subject: Re: hardare config question
References: <445236D5.5060509@aviawest.com>	
	<3DFCE70E-E4BB-40AB-B27F-99E90E8159CA@khera.org>	
	<1146246441.15712.41.camel@archimedes>
	<44564C3F.2040609@aviawest.com>	 <445651F1.9070307@jobflash.com>
	<1146509515.22037.26.camel@state.g2switchworks.com>
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guess who just bought a 3ware BBU on ebay...

Thanks for all the posts, consider me educated!

(on the importance of BBU on RAID controllers, anyway)

:)


Scott Marlowe wrote:
> On Mon, 2006-05-01 at 13:22, Tom Arthurs wrote:
>> UPS does not protect against the tech behind the rack unplugging the 
>> power cable, or an accidental power cycle from exercising the wrong 
>> switch. :)  Both are probably more common causes of failure than a total 
>> power outage.
>>
>> Erik Myllymaki wrote:
>>> I have been in discussion with 3ware support and after adjusting some 
>>> settings, the 3ware card in RAID 1 gets better performance than the 
>>> single drive. I guess this had everything to do with the write (and 
>>> maybe read?) cache.
>>>
>>> Of course now i am in a dangerous situation - using volatile write 
>>> cache without a BBU.
>>>
>>> If I were to use a UPS to ensure a soft shutdown in the event of power 
>>> loss, am I somewhat as safe as if I were to purchase a BBU for this 
>>> RAID card?
> 
> Nor does it prevent an electrician from dropping a tiny piece of wire
> into a power conditioner, causing a feedback that blows the other two
> power conditioners, all three industrial UPSes, and the switch that
> allows the Diesal generator to take over.
> 
> When that happened to me, I had the only database server in the company
> to come back up 100% in tact.  You can guess by now I also had the only
> database server with battery backed cache...
> 
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