On Sun, 21 Sep 2003, Andrew Herdman wrote: I put the same question. I get no response. > Pardon me if my assumption was incorrect, but I was under the belief that > when using software RAID1, that when reads occurred on the RAID device that > it would read from both drives in a striped fashion similar to how RAID0 > works to improve the speed of the md devices. I am actually seeing this, > but it appears that the reads on each drive are continuing for 10 to 20 > seconds before moving onto the next drive and then another 10-20 seconds and > back again. This is not allowing for any performance increase, it just lets > the drives rest alternately. > > This link http://www.whine.com/~andrew/alternating_disk.png is a gkrellm > snapshot of the activity, hda and hde are the two disks in the RAID array. > Each disk is the master on it's own channel. > > I also included the mdadm --query --detail info below for each RAID > partition > > how:~# mdadm --query --detail /dev/md/1 > /dev/md/1: > Version : 00.90.00 > Creation Time : Sat Jul 19 08:30:42 2003 > Raid Level : raid1 > Array Size : 62400 (60.94 MiB 63.90 MB) > Device Size : 62400 (60.94 MiB 63.90 MB) > Raid Devices : 2 > Total Devices : 2 > Preferred Minor : 1 > Persistence : Superblock is persistent > > Update Time : Mon Sep 15 08:41:38 2003 > State : dirty, no-errors > Active Devices : 2 > Working Devices : 2 > Failed Devices : 0 > Spare Devices : 0 > > > Number Major Minor RaidDevice State > 0 3 1 0 active sync > /dev/ide/host0/bus0/target0/lun0/part1 > 1 33 1 1 active sync > /dev/ide/host2/bus0/target0/lun0/part1 > UUID : faa4b7b2:4832fae8:ac2fa294:2fce1d85 > Events : 0.38 > > how:~# mdadm --query --detail /dev/md/2 > /dev/md/2: > Version : 00.90.00 > Creation Time : Sat Jul 19 08:32:18 2003 > Raid Level : raid1 > Array Size : 119140544 (113.62 GiB 121.100 GB) > Device Size : 119140544 (113.62 GiB 121.100 GB) > Raid Devices : 2 > Total Devices : 2 > Preferred Minor : 2 > Persistence : Superblock is persistent > > Update Time : Mon Sep 15 08:41:38 2003 > State : dirty, no-errors > Active Devices : 2 > Working Devices : 2 > Failed Devices : 0 > Spare Devices : 0 > > > Number Major Minor RaidDevice State > 0 3 2 0 active sync > /dev/ide/host0/bus0/target0/lun0/part2 > 1 33 2 1 active sync > /dev/ide/host2/bus0/target0/lun0/part2 > UUID : 0ad35f02:56a32094:c8301e3e:45895c16 > Events : 0.38 > > how:~# mdadm --query --detail /dev/md/3 > /dev/md/3: > Version : 00.90.00 > Creation Time : Sat Jul 19 08:31:37 2003 > Raid Level : raid1 > Array Size : 499904 (488.19 MiB 511.90 MB) > Device Size : 499904 (488.19 MiB 511.90 MB) > Raid Devices : 2 > Total Devices : 2 > Preferred Minor : 3 > Persistence : Superblock is persistent > > Update Time : Mon Sep 15 08:41:38 2003 > State : dirty, no-errors > Active Devices : 2 > Working Devices : 2 > Failed Devices : 0 > Spare Devices : 0 > > > Number Major Minor RaidDevice State > 0 3 3 0 active sync > /dev/ide/host0/bus0/target0/lun0/part3 > 1 33 3 1 active sync > /dev/ide/host2/bus0/target0/lun0/part3 > UUID : f8b2d95b:93055c43:d78427ac:197a610f > Events : 0.38 > > how:~# df -h > Filesystem Size Used Avail Use% Mounted on > /dev/md/2 112G 94G 16G 86% / > /dev/md/1 60M 16M 42M 28% /boot > > Have I configured something incorrectly? Or is this really the way RAID1 > works? > > Thanks > Andrew > -- > Andrew Herdman > andrew@whine.com - Primary E-Mail > > - > 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 > --- Catalin(ux) BOIE catab@deuroconsult.ro - 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
