On Wed, Jun 30, 2010 at 07:54:55AM +0200, Mikael Abrahamsson wrote: > On Wed, 30 Jun 2010, Roman Mamedov wrote: > > > dd if=/dev/zero of=zerofile bs=1M count=2048 conv=fdatasync,notrunc > > To be a bit more sure about accurate measurement, make sure the amount of > data you're transferring is twice the amount of RAM in the machine, the > above is only 2 gigs of data. As suggested, I did the test again and got the following result: -bash-4.1$ sudo dd if=/dev/zero of=test.dd bs=1M count=5000 conv=fdatasync,notrunc Password: 5000+0 records in 5000+0 records out 5242880000 bytes (5.2 GB) copied, 63.497 s, 82.6 MB/s -bash-4.1$ sudo dd if=/dev/zero of=test.dd bs=1M count=5000 conv=fdatasync,notrunc 5000+0 records in 5000+0 records out 5242880000 bytes (5.2 GB) copied, 18.1033 s, 290 MB/s I don't know why the second dd becomes 290MB/s and the first 82.6MB/s. -- Shaochun Wang(王绍春) <scwang@xxxxxxxxx> State Key Laboratory of Computer Science, Institute of Software, Chinese Academy of Sciences -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
