From mboxrd@z Thu Jan 1 00:00:00 1970 From: Larkin Lowrey Subject: Re: Read cache contents cleared on boot? Date: Tue, 10 Dec 2013 17:25:35 -0600 Message-ID: <52A7A2EF.8020507@nuclearwinter.com> References: <527ABDED.60902@nuclearwinter.com> <52A4BB32.9010104@rolffokkens.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from titan.nuclearwinter.com ([174.136.96.186]:46051 "EHLO mail.nuclearwinter.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750806Ab3LJXZe (ORCPT ); Tue, 10 Dec 2013 18:25:34 -0500 In-Reply-To: <52A4BB32.9010104@rolffokkens.nl> Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: Rolf Fokkens , linux-bcache@vger.kernel.org On 12/8/2013 12:32 PM, Rolf Fokkens wrote: > On 11/06/2013 11:08 PM, Larkin Lowrey wrote: >> When I boot my cache usage returns to 1.3GB even when it was nearly full >> at shutdown (as reported by bcache-status). Are the read cache contents >> not retained across a reboot? > Same here: After running for a while bcache-status reports a Total > Cache Used of 2.1GB. After reboot it's back to 910MB all the time. Did > you get an explanation for this? I never got an explanation but I have a theory. My cache has started booting with much more total cache used reported. My theory is that garbage collection is occurring on boot and that my pre-shutdown numbers contain a lot of dirty pages. I plan to verify this, when I get a chance, by forcing a garbage collection before shutdown and comparing the post GC numbers to the post boot numbers. --Larkin