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Description of problem: After a fresh build using software raid (md) the build speed is reported through /proc/mdstat as ~200k/s maybe peaking at 1.2MB/s on a six drive array. Boot almost so slow it appears hung at times. Moving to 2.6.37-2.fc15.x86_64 pushed the speed up to the expected ~66MB/s and the system was perfectly usable. The problem also did not exist in the earlier kernel (2.6.35.9-?). Version-Release number of selected component (if applicable): kernel 2.6.35.10-74.fc14.x86_64 How reproducible: 100% (on our system) Steps to Reproduce: 1. Build a software raid set with affected kernel. 2. Check /proc/mdstat 3. Speed of rebuild (and system in general) unacceptably slow. Actual results: I/O abnormally slow. Expected results: Raid build speeds and I/O at speeds closer to the actual disk performance. Additional info: # cat /proc/mdstat Personalities : [raid1] [raid6] [raid5] [raid4] md1 : active raid6 sda2[0] sdf2[5] sde2[4] sdd2[3] sdc2[2] sdb2[1] 3904940032 blocks super 1.1 level 6, 512k chunk, algorithm 2 [6/6] [UUUUUU] [======>..............] resync = 30.0% (292900408/976235008) finish=8892.0min speed=1280K/sec bitmap: 6/8 pages [24KB], 65536KB chunk md0 : active raid1 sda1[0] sdf1[5] sde1[4] sdd1[3] sdc1[2] sdb1[1] 524276 blocks super 1.0 [6/6] [UUUUUU] unused devices: <none> [root@1 ~]# uname -a Linux 1 2.6.35.10-74.fc14.x86_64 #1 SMP Thu Dec 23 16:04:50 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux -------------- # cat /proc/mdstat Personalities : [raid1] [raid6] [raid5] [raid4] md1 : active raid6 sda2[0] sdf2[5] sde2[4] sdd2[3] sdc2[2] sdb2[1] 3904940032 blocks super 1.1 level 6, 512k chunk, algorithm 2 [6/6] [UUUUUU] [======>..............] resync = 34.3% (335286144/976235008) finish=158.2min speed=67497K/sec bitmap: 6/8 pages [24KB], 65536KB chunk md0 : active raid1 sda1[0] sdf1[5] sde1[4] sdd1[3] sdc1[2] sdb1[1] 524276 blocks super 1.0 [6/6] [UUUUUU] unused devices: <none> [root@1 ~]# uname -a Linux 1 2.6.37-2.fc15.x86_64 #1 SMP Fri Jan 7 14:57:36 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
I don't see any changes in that latest F14 kernel that could cause this. Can you get the block device and queue information for the problem array under both a working and broken kernel? Run these commands on both kernels and attach the output: # cd /sys/block/md1 # grep "" * queue/*
Given 8mo of no comments and a indication that the f15 kernel was working fine, I'm closing this as NEXTRELEASE.