Updating my own post iostat shows /dev/sdb is at 100% transferring at 4MB/S So what limits a disk to 4MB/S??? On 18 March 2014 08:43, Jeff Allison <jeff.allison at allygray.2y.net> wrote: > OK todays problem. > > I have a HP N54L Microserver running centos 6.5. > > In this box I have a 3x2TB disk raid 5 array, which I am in the > process of extending to a 4x2TB raid 5 array. > > I've added the new disk --> mdadm --add /dev/md0 /dev/sdb > > And grown the array --> mdadm --grow /dev/md0 --raid-devices=4 > > Now the problem the resync speed is v slow, it refuses to rise above > 5MB, in general it sits at 4M. > > from looking at glances it would appear that writing to the new disk > is the bottle neck, /dev/sdb is the new disk. > > Disk I/O In/s Out/s > md0 0 0 > sda1 0 0 > sda2 0 1K > sdb1 3.92M 0 > sdc1 24.2M 54.7M > sdd1 11.2M 54.7M > sde1 16.3M 54.7M > > I partitiioned the disk with --> parted -a optimal /dev/sdb > > [root at nas ~]# parted -a optimal /dev/sdb > GNU Parted 2.1 > Using /dev/sdb > Welcome to GNU Parted! Type 'help' to view a list of commands. > (parted) p > Model: ATA ST2000DM001-1E61 (scsi) > Disk /dev/sdb: 2000GB > Sector size (logical/physical): 512B/4096B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 1049kB 2000GB 2000GB primary ntfs raid > > There is no ntfs filesystem on the disk, I've still not worked out > how to remove that flag. > > I've followed the article here --> > http://www.cyberciti.biz/tips/linux-raid-increase-resync-rebuild-speed.html > to attempt to speed it up but no joy. > > Any Ideas what I've done wrong? > > parted output > > [root at nas ~]# parted -l > Model: ATA ST31000528AS (scsi) > Disk /dev/sda: 1000GB > Sector size (logical/physical): 512B/512B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 1049kB 525MB 524MB primary ext4 boot > 2 525MB 1000GB 1000GB primary lvm > > > Model: ATA ST2000DM001-1E61 (scsi) > Disk /dev/sdb: 2000GB > Sector size (logical/physical): 512B/4096B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 1049kB 2000GB 2000GB primary ntfs raid > > > Model: ATA ST2000DM001-9YN1 (scsi) > Disk /dev/sdc: 2000GB > Sector size (logical/physical): 512B/4096B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 1049kB 2000GB 2000GB primary raid > > > Model: ATA WDC WD25EZRS-00J (scsi) > Disk /dev/sdd: 2500GB > Sector size (logical/physical): 512B/4096B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 1049kB 2000GB 2000GB primary ntfs raid > > > Model: ATA ST2000DL001-9VT1 (scsi) > Disk /dev/sde: 2000GB > Sector size (logical/physical): 512B/4096B > Partition Table: msdos > > Number Start End Size Type File system Flags > 1 1049kB 2000GB 2000GB primary raid