Hello Neil, This is my init script's one part: blockdev --setra 2048 /dev/nb0 blockdev --setra 2048 /dev/nb1 blockdev --setra 2048 /dev/nb2 blockdev --setra 2048 /dev/nb3 blockdev --setra 2048 /dev/md1 blockdev --setra 2048 /dev/md2 blockdev --setra 2048 /dev/md3 blockdev --setra 2048 /dev/md4 blockdev --setra 4096 /dev/md31 :-) This is the "default" for me. The test is have made with this settings. The problem is somewhere else.... Thanks Janos ----- Original Message ----- From: "Neil Brown" <neilb@xxxxxxx> To: "JaniD++" <djani22@xxxxxxxxxxxxx> Cc: <linux-raid@xxxxxxxxxxxxxxx> Sent: Sunday, November 27, 2005 12:27 AM Subject: Re: RAID0 performance question > On Saturday November 26, djani22@xxxxxxxxxxxxx wrote: > > Hello list, > > > > I have searching the bottleneck of my system, and found something what i > > cant cleanly understand. > > > > I have use NBD with 4 disk nodes. (raidtab is the bottom of mail) > > > > The cat /dev/nb# >/dev/null makes ~ 350 Mbit/s on each nodes. > > The cat /dev/nb0 + nb1 + nb2 + nb3 in one time parallel makes ~ 780-800 > > Mbit/s. - i think this is my network bottleneck. > > > > But the cat /dev/md31 >/dev/null (RAID0, the sum of 4 nodes) only makes > > ~450-490 Mbit/s, and i dont know why.... > > > > Somebody have an idea? :-) > > Try increasing the read-ahead setting on /dev/md31 using 'blockdev'. > network block devices are likely to have latency issues and would > benefit from large read-ahead. > > NeilBrown > - > 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 - 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
