From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Dunn Subject: Re: unbelievably bad performance: 2.6.27.37 and raid6 Date: Sun, 01 Nov 2009 18:55:24 -0500 Message-ID: <4AEE1FEC.2090809@gmail.com> References: <200911011241.40735.tfjellstrom@shaw.ca> <200911011647.41259.tfjellstrom@shaw.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200911011647.41259.tfjellstrom@shaw.ca> Sender: linux-raid-owner@vger.kernel.org To: tfjellstrom@shaw.ca Cc: NeilBrown , Jon Nelson , LinuxRaid , pernegger@gmail.com List-Id: linux-raid.ids Thanks for the update Neil, good to have something to look forward to. I am using Ubuntu 9.10, hopefully the new kernel will be incorporated sometime in the near future. In the mean time I will back everything up and create the ARRAY all over again. Thomas Fjellstrom wrote: > On Sun November 1 2009, NeilBrown wrote: > >> On Mon, November 2, 2009 6:41 am, Thomas Fjellstrom wrote: >> >>> On Sun November 1 2009, Andrew Dunn wrote: >>> >>>> Are we to expect some resolution in newer kernels? >>>> >>> I assume all of the new per-bdi-writeback work going on in .33+ will >>> have a >>> large impact. At least I'm hoping. >>> >>> >>>> I am going to rebuild my array (backup data and re-create) to modify >>>> the chunk size this week. I hope to get a much higher performance when >>>> increasing from 64k chunk size to 1024k. >>>> >>>> Is there a way to modify chunk size in place or does the array need to >>>> be re-created? >>>> >>> This I'm not sure about. I'd like to be able to reshape to a new chunk >>> size >>> for testing. >>> >> Reshaping to a new chunksize is possible with the latest mdadm and >> kernel, but I would recommend waiting for mdadm-3.1.1 and 2.6.32. >> With the current code, a device failure during reshape followed by an >> unclean shutdown while reshape is happening can lead to unrecoverable >> data loss. Even a clean shutdown before the shape finishes in that case >> might be a problem. >> > > That's good to know. Though I'm stuck with 2.6.26 till the performance > regressions in the io and scheduling subsystems are solved. > > >> NeilBrown >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> > > > -- Andrew Dunn http://agdunn.net