On Thu, Nov 20, 2008 at 03:39:40PM +0800, Nick Cheng wrote: > Hi Michael, > I will get around handling your issue. > Thanks for your kindly patience, > Hello, Was this issue resolved? I'm seeing similar behaviour.. I think it's related to flushing the controller cache? Waiting a while (after the disk leds stop blinking) performance is back to normal.. -- Pasi > -----Original Message----- > From: Andrew Morton [mailto:akpm@xxxxxxxxxxxxxxxxxxxx] > Sent: Thursday, November 20, 2008 9:18 AM > To: Michael Fuckner > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx; Nick Cheng; > Erich Chen > Subject: Re: Performance issues with Areca 1680 SAS Controllers > > (cc's added) > > On Wed, 19 Nov 2008 13:16:56 +0100 > Michael Fuckner <michael@xxxxxxxxxxx> wrote: > > > Hi, > > > > I am using an Areca 1680-SAS-Controller with 16 SAS-HDD (Seagate 1TB > > ST31000640SS). I set up a Raid6 with all 16 disks and formatted it with > > XFS. The Controller has 512MB RAM and a BBU. The OS is installed to > > another disk attached to the onboard AHCI controller. > > > > After doing some IO, the areca raidset is slower compared to the rate > > directly > > after boot. > > > > > > [root@storage ~]# dd if=/dev/sdb1 of=/dev/null bs=1M count=50k > iflag=direct > > 51200+0 records in > > 51200+0 records out > > 53687091200 bytes (54 GB) copied, 59.6494 seconds, 900 MB/s > > [root@storage ~]# mount /dev/sdb1 /data > > [root@storage ~]# cd /data/ > > [root@storage data]# ./iozone -i 0 -i 1 -s 32g -r 16m -S 6144 -t 8 -+r > > -o >raid6_sync_t8.log > > [root@storage data]# cd > > [root@storage ~]# umount /data/ > > [root@storage ~]# dd if=/dev/sdb1 of=/dev/null bs=1M count=50k > iflag=direct > > 51200+0 records in > > 51200+0 records out > > 53687091200 bytes (54 GB) copied, 76.4036 seconds, 703 MB/s > > > > I tested different Versions of Linux (Centos 5.2, OpenSUSE 11, Debian > > Lenny) and Vanilla kernels 2.6.22-2.6.27, all show this behaviour. > > > > Idea why the device slows down after IO- or better: how to keep the high > > rate? Is this reproducible foer Areca SATA Controllers (Type 11XX and > 12XX) > > > > Regards, > > Michael! > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
