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Message-ID: <5265679A.4050600@redhost.ro> Date: Mon, 21 Oct 2013 20:42:50 +0300 From: Andrei Banu <andrei.banu@...host.ro> To: linux-ext4@...r.kernel.org, Zheng Liu <gnehzuil.liu@...il.com> Subject: Re: Weird jbd2 I/O load Hi, Meantime I've created another md device (just 5GB) and I've redone the tests. I believe this is easier and less risky than remounting an used md device. root [/home2]# mount -l | grep md3 /dev/md3 on /home2 type ext4 (rw,barrier=0) root [/home2]# dd bs=2M count=64 if=/dev/zero of=test6 conv=fdatasync 64+0 records in 64+0 records out 134217728 bytes (134 MB) copied, 12.3287 s, 10.9 MB/s So the speed issue is still with us I believe. Is there some way to check the barrier is really set to 0? Thanks a lot! On 10/21/2013 4:53 PM, Zheng Liu wrote: > Hi Andrei, > > Could you please disable barrier for ext4 and try your 'dd' test again? > $ sudo mount -t ext4 -o remount,barrier=0 ${DEV} ${MNT} > > *WARNING: you could lost your data with barrier=0 when you get a power > failure or cold reset.* > > We have met a similar problem that is because some SSDs couldn't handle > barrier command properly. > > Regards, > - Zheng -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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