[Tfug] Really slow mdadm resyncing
Harry McGregor
micros at osef.org
Sun Jun 17 23:35:30 MST 2007
Hi Matt,
It sounds like the drives are not in DMA mode.
Can you apt-get install hdparm and run the following:
To see if DMA mode is set run this:
hdparm /dev/hde
hdparm /dev/hdf
To do a basic benchmark on the drives, run this:
hdparm -tT /dev/hde
hdparm -tT /dev/hdf
Harry
Matt Jacob wrote:
> Hey guys:
>
> I just set up a box with Debian etch, and I'm using mdadm with 2 IDE
> drives in RAID1. I rsync'd about 50G of data to the box today, and
> that finished at around 9:00 or 10:00 this morning. More than twelve
> hours later, the RAID is still "active, resyncing", and I can't figure
> out why. I don't even know what that means (I thought the status was
> supposed to be "dirty" while recovering).
>
> Here's the output from mdadm:
>
> ned:~# mdadm -D /dev/md2
> /dev/md2:
> Version : 00.90.03
> Creation Time : Sat Jun 16 11:45:51 2007
> Raid Level : raid1
> Array Size : 159139776 (151.77 GiB 162.96 GB)
> Device Size : 159139776 (151.77 GiB 162.96 GB)
> Raid Devices : 2
> Total Devices : 2
> Preferred Minor : 2
> Persistence : Superblock is persistent
>
> Update Time : Sat Jun 16 18:36:02 2007
> State : active, resyncing
> Active Devices : 2
> Working Devices : 2
> Failed Devices : 0
> Spare Devices : 0
>
> Rebuild Status : 64% complete
>
> UUID : 7f38bf9f:27f5bf50:05d2898a:691e38c1
> Events : 0.9
>
> Number Major Minor RaidDevice State
> 0 33 3 0 active sync /dev/hde3
> 1 33 67 1 active sync /dev/hdf3
>
>
> And then there's this, which shows a pathetic 1M/s transfer rate:
>
> ned:~# cat /proc/mdstat
> Personalities : [raid1]
> md2 : active raid1 hde3[0] hdf3[1]
> 159139776 blocks [2/2] [UU]
> [============>........] resync = 64.3% (102406080/159139776)
> finish=830.1min speed=1137K/sec
>
> md1 : active raid1 hde2[0] hdf2[1]
> 746944 blocks [2/2] [UU]
>
> md0 : active raid1 hde1[0] hdf1[1]
> 192640 blocks [2/2] [UU]
>
> unused devices: <none>
>
>
> The strange thing is that my speed_limit_min is set to 50000, which
> should be 50M/s:
>
> ned:~# cat /proc/sys/dev/raid/speed_limit_min
> 50000
>
> Any ideas? Am I missing something? If I can't get better performance
> out of this thing, I'm gonna go back to my poor man's RAID which
> consisted of a nightly rsync job between the two drives.
>
> Matt
>
> P.S. Here are my system specs: Athlon 1200 MHz, 768 M RAM, (2) IDE ATA100 drives
>
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