Re: [RFC PATCH 0/5] Btrfs: Add hot data tracking functionality

From: Chris Samuel <chris@csamuel.org>
To: linux-btrfs@vger.kernel.org
Cc: Ben Chociej <bchociej@gmail.com>,
	diegocg@gmail.com, chris.mason@oracle.com,
	linux-fsdevel@vger.kernel.org, cmm@us.ibm.com,
	bcchocie@us.ibm.com, mrlupfer@us.ibm.com, crscott@us.ibm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/5] Btrfs: Add hot data tracking functionality
Date: Wed, 28 Jul 2010 22:28:19 +1000	[thread overview]
Message-ID: <201007282228.23360.chris@csamuel.org> (raw)
In-Reply-To: <AANLkTi=x9q1XOu_6F2hOv_ZPoM+McKz9Nv2Q5GZNfa4a@mail.gmail.com>

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On Wed, 28 Jul 2010 09:18:23 am Ben Chociej wrote:

> Yes, that's correct. It's likely not going to be a cache in the
> traditional sense, since the entire capacity of both HDD and SSD would
> be available.

To me that sounds like an HSM type arrangement, with most frequently used data 
on the highest performing media and less frequently touched data getting 
shunted down the chain to SAS, SATA and then tape and/or MAID type devices.

Certainly interesting from my HPC point of view in that I can see it being 
useful to parallel filesystems like Ceph if this "just happens".

I guess real HSM devotees would want policies for migration downstream.. ;-)

cheers,
Chris
-- 
 Chris Samuel  :  http://www.csamuel.org/  :  Melbourne, VIC

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