From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philip Molter Subject: Re: Software RAID & Filesystem Cache Date: Sat, 07 Aug 2004 09:04:48 -0500 Sender: linux-raid-owner@vger.kernel.org Message-ID: <4114E180.7000902@corp.texas.net> References: <4112731A.5030000@h3c.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4112731A.5030000@h3c.com> To: linux-raid@vger.kernel.org List-Id: linux-raid.ids > /sys % find . | grep ahead > ./block/hdf/queue/read_ahead_kb > ./block/hdg/queue/read_ahead_kb > ./block/hdc/queue/read_ahead_kb > ./block/hda/queue/read_ahead_kb Yeah, these definitely have no effect on how much is being read from the disks. There is a direct correlation, though, between the chunk size on the raid0 portion of the raid10 and the amount of data that is read. If you increase the chunk size, you increase not just the number of bytes read from the disks. There's something seriously messed up with software RAID10. It's practically unusable for high-load situations where before it was perfectly fine.