From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Cousins Subject: Re: bad performance on RAID 5 Date: Thu, 18 Jan 2007 13:29:25 -0500 Message-ID: <45AFBC85.8020500@maine.edu> References: <45AE9640.1040500@start.no> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45AE9640.1040500@start.no> Sender: linux-raid-owner@vger.kernel.org To: Sevrin Robstad Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Sevrin Robstad wrote: > I'm suffering from bad performance on my RAID5. > > a "echo check >/sys/block/md0/md/sync_action" > > gives a speed at only about 5000K/sec , and HIGH load average : What do you get when you try something like: time dd if=/dev/zero of=/mount-point/test.dat bs=1024k count=1024 where /mount-point is where /dev/md0 is mounted. This will create a 1 GiB file and it will tell you how long it takes to create it. Also, I'd try running Bonnie++ on it to see what the different performance values are. I don't know a lot about the md sync process but I remember having my sync action stuck at a low value at one point and it didn't have anything to do with the performance of the RAID array in general. Steve > # uptime > 20:03:55 up 8 days, 19:55, 1 user, load average: 11.70, 4.04, 1.52 > > kernel is 2.6.18.1.2257.fc5 > mdadm is v2.5.5 > > the system consist of an athlon XP1,2GHz and two Sil3114 4port S-ATA PCI > cards with a total of 6 250gb S-ATA drives connected. > > [root@compaq ~]# mdadm --detail /dev/md0 > /dev/md0: > Version : 00.90.03 > Creation Time : Tue Dec 5 00:33:01 2006 > Raid Level : raid5 > Array Size : 1218931200 (1162.46 GiB 1248.19 GB) > Device Size : 243786240 (232.49 GiB 249.64 GB) > Raid Devices : 6 > Total Devices : 6 > Preferred Minor : 0 > Persistence : Superblock is persistent > > Update Time : Wed Jan 17 23:14:39 2007 > State : clean > Active Devices : 6 > Working Devices : 6 > Failed Devices : 0 > Spare Devices : 0 > > Layout : left-symmetric > Chunk Size : 256K > > UUID : 27dce477:6f45d11b:77377d08:732fa0e6 > Events : 0.58 > > Number Major Minor RaidDevice State > 0 8 1 0 active sync /dev/sda1 > 1 8 17 1 active sync /dev/sdb1 > 2 8 33 2 active sync /dev/sdc1 > 3 8 49 3 active sync /dev/sdd1 > 4 8 65 4 active sync /dev/sde1 > 5 8 81 5 active sync /dev/sdf1 > [root@compaq ~]# > > > Sevrin > - > 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 -- ______________________________________________________________________ Steve Cousins, Ocean Modeling Group Email: cousins@umit.maine.edu Marine Sciences, 452 Aubert Hall http://rocky.umeoce.maine.edu Univ. of Maine, Orono, ME 04469 Phone: (207) 581-4302