From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id E3C8A7F52 for ; Thu, 27 Jun 2013 20:56:15 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay2.corp.sgi.com (Postfix) with ESMTP id CC84230404E for ; Thu, 27 Jun 2013 18:56:15 -0700 (PDT) Received: from ipmail05.adl6.internode.on.net (ipmail05.adl6.internode.on.net [150.101.137.143]) by cuda.sgi.com with ESMTP id bQotofw5Rit8wGJB for ; Thu, 27 Jun 2013 18:56:14 -0700 (PDT) Date: Fri, 28 Jun 2013 11:56:10 +1000 From: Dave Chinner Subject: Re: sizing log - is there a too big? Message-ID: <20130628015610.GH32195@dastard> References: <55C24454-59E9-4285-9A4C-C4BD24EDBEEC@gmail.com> <20130627014810.GA29790@dastard> <73A9FC1C-854D-4C23-B560-FEEF64A3001B@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <73A9FC1C-854D-4C23-B560-FEEF64A3001B@gmail.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: aurfalien Cc: xfs@oss.sgi.com On Thu, Jun 27, 2013 at 08:58:06AM -0700, aurfalien wrote: > > On Jun 26, 2013, at 6:48 PM, Dave Chinner wrote: > > > On Wed, Jun 26, 2013 at 04:56:31PM -0700, aurfalien wrote: > >> Hi all, > >> > >> Wondering if my log being just under 2GB is a bad idea. > >> > >> Noticing flush-253:2/kcopyd which is my XFS file system getting > >> really high load avg and wait times via top). > > > > What has the log size got to do with something that is happening at > > the block layer? What's your storage config? > > > >> Doing a simple rsync over NFS and after a bit, the system gets to a load of 24.... yikes... > > > > Let me guess - 24 nfsds blocked waiting for kcopyd to do it's stuff? > > > > Load average going up when the NFS server is busy generally means > > your IO subsystem is heavily loaded - it's not uncommon to see large > > NFS servers that are extremely busy sustain load averages over a > > 100 (or even 1000) for hours/days on end.... > > > >> Upon killing the rsync, I am seeing loads going down to sub 1 > >> after about 10 min. I have repeated this to verify 10 min. > > > > Sure. Processes blocked on IO contribute to the load average. Kill > > the IO load, and the load average will return to nothing in 10-15 > > minutes. > > > Not so fast my fine feathered friend. > > Same work load, same hardware. > > Only diff is; > > External log, its 2GB > And its Centos 6.4 which was previously 5.9. Oh, you're comparing behaviour between kernels 5 years in age difference. Well, things change, and a change of load average for the same workload between very different kernels is no unexpected. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs