Hi, ----- Original Message ----- From: "Al Boldi" <a1426z@xxxxxxxxx> To: "JaniD++" <djani22@xxxxxxxxxxxxx> Cc: <linux-raid@xxxxxxxxxxxxxxx>; "Neil Brown" <neilb@xxxxxxx> Sent: Sunday, November 27, 2005 4:39 PM Subject: Re: RAID0 performance question > Neil Brown wrote: > > On Saturday November 26, djani22@xxxxxxxxxxxxx wrote: > > > > > > The cat /dev/nb# >/dev/null makes ~ 350 Mbit/s on each nodes. > > Why is this so slow? Yes. :-) This system tries to serv about 500-800 downloads. The final goal is the 1k! ;-) And this point why i am asking the list, because the HW performance is much more without raid0 layer. :-/ The 780-800 Mbit is "almost" enough to 1k downloaders. > Or is this the max node-HD throughput? Yes. > What's the node HW config? P4-3G -HT 12x 200Gb hdd (10 IDE+2 SATA) 2G Ram realtek gige. RAID5 inside! ;-) > > > > The cat /dev/nb0 + nb1 + nb2 + nb3 in one time parallel makes ~ 780-800 > > > Mbit/s. - i think this is my network bottleneck. > > How much do you get w/ nb0+1,2,3 and nb0+1+2,3 respectively? I unable to test write, because this is a productive system. Think this value is about 75-80 per node and ~200-250 in md31. > > > > 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. > > Also try larger chunk-size ~4mb. Ahh. This is what i can't do. :-( I dont know how to backup 8TB! ;-) Thanks, Janos > > -- > Al > > - > 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
