From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sage Weil Subject: RE: Adding compression/checksum support for bluestore. Date: Wed, 30 Mar 2016 18:24:57 -0400 (EDT) Message-ID: References: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from cobra.newdream.net ([66.33.216.30]:60413 "EHLO cobra.newdream.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752261AbcC3WZH (ORCPT ); Wed, 30 Mar 2016 18:25:07 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Vikas Sinha-SSI Cc: Allen Samuels , Igor Fedotov , ceph-devel On Wed, 30 Mar 2016, Vikas Sinha-SSI wrote: > > [snip] > > If I understand correctly, then there would still be a cost associated with writing dis-contiguously > to disk. In cases such as this where the resources for compression are not easily available, I wonder > if it is reasonable to simply not do compression for that Write. The cost of not compressing would be > a missed space optimization, but the cost of compressing in any and all cases could be significant to latency. I also like this better than the split pextent complexity. sage