From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:42451 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750796AbaABIuW (ORCPT ); Thu, 2 Jan 2014 03:50:22 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1Vydyu-0001Yq-1C for linux-btrfs@vger.kernel.org; Thu, 02 Jan 2014 09:50:20 +0100 Received: from ip68-231-22-224.ph.ph.cox.net ([68.231.22.224]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 02 Jan 2014 09:50:20 +0100 Received: from 1i5t5.duncan by ip68-231-22-224.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 02 Jan 2014 09:50:20 +0100 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: Migrate to bcache: A few questions Date: Thu, 2 Jan 2014 08:49:58 +0000 (UTC) Message-ID: References: <52C1990D.9060704@gmail.com> <52C476B8.2040601@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Austin S Hemmelgarn posted on Wed, 01 Jan 2014 15:12:40 -0500 as excerpted: > On 12/30/2013 11:02 AM, Austin S Hemmelgarn wrote: >> >> As an alternative to using bcache, you might try something simmilar to >> the following: >> 64G SSD with /boot, /, and /usr Other HDD with /var, /usr/portage, >> /usr/src, and /home tmpfs or ramdisk for /tmp and /var/tmp >> This is essentially what I use now, and I have found that it >> significantly improves system performance. >> > On this specific note, I would actually suggest against putting the > portage tree on btrfs, it makes syncing go ridiculously slow, > and it also seems to slow down emerge as well. Interesting observation. I had not see it here (with the gentoo tree and overlays on btrfs), but that's very likely because all my btrfs are on SSD, as I upgraded to both at the same time, because my previous default filesystem choice, reiserfs, isn't well suited to SSD due to excessive writing due to the journaling. I do know slow syncs and portage dep-calculations were one of the reasons I switched to SSD (and thus btrfs), however. That was getting pretty painful on spinning rust, at least with reiserfs. And I imagine btrfs on single-device spinning rust would if anything be worse at least for syncs, due to the default dup metadata, meaning at least three writes (and three seeks) for each file, once for the data, twice for the metadata. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman