----- Original Message ----- > From: "Reindl Harald" <h.reindl at thelounge.net> > To: "CentOS mailing list" <centos at centos.org> > Cc: "David C. Miller" <millerdc at fusion.gat.com> > Sent: Thursday, April 11, 2013 4:17:18 PM > Subject: Re: [CentOS] RAID 6 - opinions > > > > Am 12.04.2013 01:13, schrieb David C. Miller: > > dd if=/dev/zero of=/backup/5GB.img count=5000 bs=1M > > 5000+0 records in > > 5000+0 records out > > 5242880000 bytes (5.2 GB) copied, 10.8293 s, 484 MB/s > > aha, you have 16 GB RAM, write 5 GB to the disk which > is easily buffered into RAM and think this measures > anything? > > do the same with 32 GB instead 5 GB > > Good call, I did not even think about that. Here is a 31GB file write. dd if=/dev/zero of=/backup/30GB.img count=30000 bs=1M 30000+0 records in 30000+0 records out 31457280000 bytes (31 GB) copied, 78.041 s, 403 MB/s David.