From mboxrd@z Thu Jan 1 00:00:00 1970 From: aragonx@dcsnow.com Subject: Re: How to boost performance Date: Thu, 17 Jun 2010 15:56:26 -0400 Message-ID: References: <20100617100109.32a20ffa@natsu> <20100617221300.3e30afe0@natsu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Roman Mamedov Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids > time dd if=/dev/zero of=zerofile bs=1M count=2048 conv=fdatasync,notrunc > 2048+0 records in > 2048+0 records out > 2147483648 bytes (2.1 GB) copied, 28.728 s, 74.8 MB/s > > real 0m28.732s > user 0m0.004s > sys 0m23.600s > > time dd if=/dev/zero of=zerofile bs=1M count=6144 conv=fdatasync,notrunc > 6144+0 records in > 6144+0 records out > 6442450944 bytes (6.4 GB) copied, 196.618 s, 32.8 MB/s > > real 3m16.622s > user 0m0.012s > sys 0m27.726s Bleh, sorry for so many posts. I ran the same DD test on my OS disk that is on the same controller as 4 of the RAID disks above. It did much better although that drive is slower than the ones that belong to the RAID. time dd if=/dev/zero of=zerofile bs=1M count=6144 conv=fdatasync,notrunc 6144+0 records in 6144+0 records out 6442450944 bytes (6.4 GB) copied, 109.823 s, 58.7 MB/s real 1m49.827s user 0m0.014s sys 0m20.965s -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.