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From: Stan Hoeppner <stan@hardwarefreak.com>
To: linux-raid@vger.kernel.org
Subject: Re: HBA Adaptor advice
Date: Fri, 20 May 2011 15:12:56 -0500	[thread overview]
Message-ID: <4DD6CB48.6050701@hardwarefreak.com> (raw)
In-Reply-To: <20110520200100.GF4759@bitfolk.com>

On 5/20/2011 3:01 PM, Andy Smith wrote:

> It's a shame; maybe there will be disks with battery-backed cache
> one day.

You'll never see a cache DRAM BBU built into a drive.  If this *concept*
were to be implemented it would be done with flash and a capacitor
instead of a BBU.  The capacitor would be sized to hold just enough
juice to power the ASIC, flash chip, and related circuitry, and write
the cache DRAM contents to the flash chip after sensing power to the
card has been lost.

Many higher end RAID cards already have flash backup of the cache DRAM
in addition to, in instead of, a BBU.

-- 
Stan

  reply	other threads:[~2011-05-20 20:12 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-19 12:26 HBA Adaptor advice Ed W
2011-05-19 12:36 ` Roman Mamedov
2011-05-19 12:43   ` Mathias Burén
2011-05-19 14:06 ` Michael Sallaway
2011-05-19 19:10 ` Thomas Harold
2011-05-19 21:12   ` Rudy Zijlstra
2011-05-19 21:07 ` Brad Campbell
2011-05-20 20:58   ` Tobias McNulty
2011-05-20 21:23     ` Brad Campbell
2011-05-20  2:08 ` Andy Smith
2011-05-20  5:30   ` Stan Hoeppner
2011-05-21  9:52     ` Ed W
2011-05-20  7:33   ` Ed W
2011-05-20 10:21     ` Stan Hoeppner
2011-05-21 11:17       ` Ed W
2011-05-21 11:29         ` Rudy Zijlstra
2011-05-21 11:54           ` Ed W
2011-05-21 17:37             ` Leslie Rhorer
2011-05-22  9:41             ` Stan Hoeppner
2011-05-22 10:03               ` Rudy Zijlstra
2011-05-23  9:32                 ` Ed W
2011-05-21 17:05           ` Leslie Rhorer
2011-05-22  9:04         ` Stan Hoeppner
2011-05-22 10:09           ` Brad Campbell
2011-05-22 19:25             ` Stan Hoeppner
2011-05-22 20:57               ` Tobias McNulty
2011-05-22 21:13                 ` Johannes Truschnigg
2011-05-23  9:48                   ` Ed W
2011-05-23 10:44                     ` John Robinson
2011-05-22 23:19               ` Brad Campbell
2011-05-23  4:09                 ` Roman Mamedov
2011-05-23  5:54                   ` Brad Campbell
2011-05-23  6:08                     ` Roman Mamedov
2011-05-23 10:42                     ` Stan Hoeppner
2011-05-23 11:35                       ` David Brown
2011-05-23  6:54                 ` Stan Hoeppner
2011-05-23  7:23                   ` Brad Campbell
2011-05-22 23:44               ` Brad Campbell
2011-05-23  0:07                 ` Brad Campbell
2011-05-23  5:30                   ` Stefan /*St0fF*/ Hübner
2011-05-23 10:18                     ` Ed W
2011-05-23  9:58                 ` Stan Hoeppner
2011-05-23 10:33                   ` Ed W
2011-05-23 11:21                     ` Stan Hoeppner
2011-05-20 12:18     ` Joe Landman
2011-05-20 12:34       ` Roman Mamedov
2011-05-20 12:36         ` Mathias Burén
2011-05-20 12:48         ` Joe Landman
2011-05-20 13:21       ` Ed W
2011-05-20 14:23         ` Joe Landman
2011-05-20 20:01       ` Andy Smith
2011-05-20 20:12         ` Stan Hoeppner [this message]
2011-05-20 20:24         ` Drew
2011-05-20 20:58           ` Stan Hoeppner
     [not found]             ` <4DD7A100.2010807@wildgooses.com>
2011-05-22  8:13               ` Stan Hoeppner
  -- strict thread matches above, loose matches on Subject: below --
2011-05-23  2:11 Jim Schatzman
2011-05-23  3:39 ` Tobias McNulty
2011-05-23 10:42   ` Ed W
2011-05-23 11:14 HBA Adaptor Advice Ed W
2011-05-23 11:55 ` Joe Landman

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