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I have setup a RAID 1 array with 2 Seagate 1.5TB SATA ST31500341AS drives for my NAS using Openfiler.

The system has been up for over 17hrs and the array is still syncing, speed has dropped from 16MB/s down to a pathetic 3.5M/B over the period.

Is that normal?

What happen if I have to replace one of the drive in future due to drive failure, does it have to re-sync for a whole day again? Will the NAS still being usable during the re-sync?

[root@openfiler chris]# cat /proc/mdstat 
Personalities : [raid6] [raid5] [raid4] [raid10] [raid1] 
md0 : active raid1 sdc1[1] sdb1[0]
      1465135936 blocks [2/2] [UU]
      [================>....]  resync = 80.1% (1173746816/1465135936) finish=1391.1min speed=3489K/sec

EDIT: OS is installed on a separate drive with no RAID. TIA

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1 Answer 1

up vote 0 down vote accepted

you could change:

/proc/sys/dev/raid/speed_limit_min
/proc/sys/dev/raid/speed_limit_max

to higher numbers. Some of the OS defaults are not really optimized for today's higher speed drives.

Depending on the bus bandwidth and system activity, 1.5 terabytes could take 20+ hours. If a drive fails, you will just split IO between your normal activity and reconstruction. Yes, you would have to allow it to reconstruct if there was a failure, but, it would still be available to use.

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Yep, it works. Thanks a lot. I learned by rebuilding the RAID array again after one of the Seagate 1.5TB 7200.11 disk decided not to play ball anymore. I'm using 2x WD 500GB disks instead, and it took less than 2 hours for the build process. –  Chris Jul 5 '10 at 17:29

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