[DRBD-user] DRBD 0.7.23 over MD raid performance

[Duane Cox]

I'm curious, how is your WRITE performance in comparison?


----- Original Message ----- 
From: "Laurent CARON" <lcaron at lncsa.com>
To: <drbd-user at lists.linbit.com>
Sent: Friday, April 13, 2007 9:10 AM
Subject: [DRBD-user] DRBD 0.7.23 over MD raid performance


> Hi,
> 
> I did set up two machines with drbd, heartbeat, raid ... and i'm still
> wondering why the read throughput using drbd is as much as 4 times less
> than using md.
> 
> hdparm -tT /dev/md2
> 
> /dev/md2:
>  Timing cached reads:   6496 MB in  2.00 seconds = 3251.89 MB/sec
>  Timing buffered disk reads:  1114 MB in  3.01 seconds = 370.59 MB/sec
> 
> hdparm -tT /dev/drbd0
> 
> /dev/drbd0:
>  Timing cached reads:   6532 MB in  2.00 seconds = 3270.07 MB/sec
>  Timing buffered disk reads:  322 MB in  3.01 seconds = 106.88 MB/sec
> 
> Please note that md2 is the underlying device that holds drbd0
> 
> Thanks
> 
> Laurent
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