This read-only file contains information about the status of currently running array and shows rebuilding speed:
# cat /proc/mdstat Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] md0 : active raid10 sdc3[0] sdk3[10] sdf3[9] sde3[12] sdi3[13] sdh3[14] sdg3[4] sda3[3] sdb3[2] sdd3[1] 17572185216 blocks super 1.0 64K chunks 2 near-copies [12/10] [UUUUUUU_UUU_] [=============>.......] resync = 69.7% (12249957440/17572185216) finish=462.0min speed=191956K/sec bitmap: 8/9 pages [32KB], 1048576KB chunk
To see your Linux kernel speed limits imposed on the RAID reconstruction use:
cat /proc/sys/dev/raid/speed_limit_max 200000 cat /proc/sys/dev/raid/speed_limit_min 5000
To increase speed, enter:
echo VALUE > /proc/sys/dev/raid/speed_limit_min echo VALUE > /proc/sys/dev/raid/speed_limit_maxT
To provide details about /dev/md0 raid arrray including status and health report:
# mdadm --detail /dev/md0 /dev/md0: Version : 1.0 Creation Time : Tue May 29 14:55:47 2012 Raid Level : raid10 Array Size : 17572185216 (16758.14 GiB 17993.92 GB) Used Dev Size : 2928697536 (2793.02 GiB 2998.99 GB) Raid Devices : 12 Total Devices : 10 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Thu Mar 5 02:10:48 2015 State : active, degraded, resyncing Active Devices : 10 Working Devices : 10 Failed Devices : 0 Spare Devices : 0 Layout : near=2 Chunk Size : 64K Resync Status : 69% complete Name : 0 UUID : ce9a3c83:2a4b6b63:413f682e:923f6790 Events : 11836407 Number Major Minor RaidDevice State 0 8 35 0 active sync set-A /dev/sdc3 1 8 51 1 active sync set-B /dev/sdd3 2 8 19 2 active sync set-A /dev/sdb3 3 8 3 3 active sync set-B /dev/sda3 4 8 99 4 active sync set-A /dev/sdg3 14 8 115 5 active sync set-B /dev/sdh3 13 8 131 6 active sync set-A /dev/sdi3 14 0 0 14 removed 12 8 67 8 active sync set-A /dev/sde3 9 8 83 9 active sync set-B /dev/sdf3 10 8 163 10 active sync set-A /dev/sdk3 22 0 0 22 removed # mdadm -D /dev/md0 ##SAME AS ABOVE
To do real-world disk write test in linux is:
# hdparm -t /dev/md0 /dev/md0: Timing buffered disk reads: 1142 MB in 3.01 seconds = 379.96 MB/sec
