From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zachary Palmer Subject: bcache on a laptop Date: Thu, 19 Sep 2013 19:10:03 -0400 Message-ID: <523B844B.8070202@bahj.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Gents, I'm still trying to get a comfy bcache installation on a laptop. To summarize thus far, 1. I have a Debian system that boots from bcache 2. No version of 3.10 that I have tested (either from the Linux git or from the bcache-stable branch of the bcache git) will allow the laptop to sleep or hibernate properly. 3. Every version of 3.11 that I have tested results in severe data corruption. (I wound up having to reinstall my system as a result.) Using 3.11.0 built from the 3.11.y branch at kernel.org, the corruption was subtle at first; eventually programs started segfaulting. Running "sync ; echo 3 > /proc/sys/vm/drop_caches" would resolve the corruption issue (I'm in writethrough mode), but the root was destroyed when corruption occurred in the middle of a nightly upgrade. 4. When corruption isn't an issue (e.g. in a 3.10 kernel), I'm getting between a 50% and 80% cache hit ratio (again in writethrough, not writeback). I'm pretty happy about that. :) 5. Creating a large number of small files seems to be quite a lot slower than it was without bcache. (For instance, installing xfce4 and its dependencies into a fresh chroot takes about two hours.) I've noticed that Debian packages in particular take longer; kernel header packages often take close to half an hour by themselves. (Can anyone posit a reason for this?) I'll be trying the 3.10.12 bcache-stable shortly, though I expect that it won't make a huge difference in the hibernation problem. I just wanted to record this information in case someone else decides to give this a go. Cheers, Zach