On Thu, 6 Jan 2005 11:13:58 +0100, Pieter Hulshoff
Hello all,
I've got a SuSe 9.1 system here, with 4 disks, 2 RAID-0 (2 disks each), and a number of non-RAID partitions on it. Neither hdparm nor manual file copying seems to indicated a significant difference in speed between the RAID and the non-RAID partitions. The two drives of each RAID-0 partition are not on the same IDE connector. Any thoughts on what might cause this, and how I might fix it? I thought there'd at least be _some_ advantage to using RAID-0.
Regards,
Pieter Hulshoff
I agree with your thought and have no suggestion re: raid 0. For pure disk performance, one tuning trick I found with 9.2 is to use "noapic" on the kernel boot line. It increased my disk speed 20-30%. If you have more than one CPU, you may not want to do this. i.e. APIC is used in SMP setups, and I don't know what happens if you disable it. Also, how are you measuring performance? I use "iostat -d 5", but you have to install that via yast. For a read test, I do md5sum /dev/hdc1. Without noapic, I get 70,000-80,000 blocks/sec. With noapic, I get 100,000 or a little more For a copy test, I do "dd if=/dev/hdc of=/dev/hde". It tends to be 50-60,000 without noapic, and 70-80,000 with noapic. The above numbers are from memory, so I may have them wrong, but the concept is right. FYI: I am using the Adpatec PCI dual-channel ATA/133 controller with each disk on a different controller. My CPU is a P4 3.1 GHz. Greg -- Greg Freemyer