From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: Single disk performance Date: Mon, 29 Jun 2009 08:41:49 -0400 Message-ID: <20090629124149.GF3951@think> References: <4A44DB23.5000400@austin.ibm.com> <20090626205659.GD3951@think> <4A458373.4010603@austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-btrfs To: Steven Pratt Return-path: In-Reply-To: <4A458373.4010603@austin.ibm.com> List-ID: On Fri, Jun 26, 2009 at 09:26:59PM -0500, Steven Pratt wrote: > Chris Mason wrote: >> On Fri, Jun 26, 2009 at 09:28:51AM -0500, Steven Pratt wrote: >> >>> Upgraded the btrfs tree to 6-17 and all of the stability problems >>> went away on the single disk system, so not sure if this was a code >>> problem or hardware, but at least stable now. >>> Performance results updated at: >>> http://btrfs.boxacle.net/repository/single-disk/History/History.html >>> >>> The fixed to the cow path are obvious for random write, although even >>> on single disk the CPU overhead is very noticeable as the efficiency >>> graphs show. >>> >>> The good news is that now the only workload that Btrfs is not at or >>> near the top in performance for single disk is MailServer. >>> >> >> Thanks Steve, glad to hear the stability problems are gone. >> >> > Well, maybe I spoke too soon. :-( Run with this patch died in similar > way to before. My remote service console is not responding, so will > probably be Monday before I can get to the lab to restart manually. > > > I am getting messages like: > > Lots of these timeout messages, then eventually > > 18:40:32 btrfs2 kernel: [ 4459.870613] sd 0:0:1:0: [sdb] Unhandled error > code > Jun 26 18:40:32 btrfs2 kernel: [ 4459.870640] sd 0:0:1:0: [sdb] Result: > hostbyte=DID_ABORT driverbyte=DRIVER_OK > Jun 26 18:40:32 btrfs2 kernel: [ 4459.870646] end_request: I/O error, > dev sdb, sector 103359232 > > So still not sure if this is HW, but no other FS has triggered it. > I'm afraid Btrfs can't do this on its own. It needs to HW, scsi drivers or HW or scsi drivdes ;) You could try dd if=/dev/sdb of=/dev/zero bs=512 count=1 skip=103359232 Hopefully that will fall over without btrfs helping. -chris