Hi * I am using several hardware raid systems based on 3Ware, Adaptec and AC&NC hardware. The Mainboard of the test machine is a Supermicro P4DMS-6GM with two Xeon 2.4GHz Processors and 1 Gig of RAM. IDE (WD 120 Gig) disks are used in the AC&NC Jetstor III (14 disks) and in the 3Ware (7 disks). The Adaptec Raids use SCSI (Seagate) Disks. All these systems show a remarkably bad performance (max. 80 MB/s write and max. 70 MB/s read, exact figures (bonnie++,iostat) available). I am using kernel 2.4.20 without any patches (Highmem on / i2o off) and an ext3 filesystem. I have played around with different stride settings and block sizes as well as chunk sizes on the raid and experienced minor differences within the above limits. By setting echo 256 > /proc/sys/vm/max-readahead echo 128 > /proc/sys/vm/min-readahead I could convince the 3ware to read data with up to 114 MB/s. So basically I am experiencing the same bad speeds (especially write speeds) as Donghui (and others). It seems to me like there might be a common reason behind the bad performance. (the VM Layer settings?) While writing this email I just finished a bonnie++ run on a new software raid using 8 SCSI Disks: softr.8disk.64chunk,2000M:64k,13630,99,41206,41,27280,27,15278,97,156480,62,329.8,12,16,1322,81,+++++,+++,29177,99,1510,99,+++++,+++,3981,98 That's an amazing difference in reading speed to the hardware raids (soft:156480;hard:70155). I will most probably not be able to convert all my Raids to Software Raids, so I would like to reach a similar performance with the Hardware Raid. Any ideas,comments,...? Christian - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
