I am setting up an array with 14 disks. Should I create one 14 disk RAID 5 array? Or two 7 disk RAID 5 arrays, and then RAID 0 them together? I know I would have less overall space with 2 RAID 5 arrays. This is not an issue. I guess the real question is: does RAID five have a sweet spot related to the number of disks? Is there chunk size sweet spot? Does it very with number of disks? System: P3-500 (2 processors) 512 Meg ram 3 SCSI cards for disks. 1 internal LVD (80 meg/second) 2 disks (for OS) mirrored 1 disk for spare 1 external LVD (80 meg per second) 7 disks 1 external ultra-wide (40 meg per second) 7 disks All disks are 18 Gig. Will be using RedHat 9 I plan to alternate the disks on each SCSI bus. So the array would use disk in an order simular to this: a0, b0, a1, b1, a2, b2, ... This should help balance the load on the 2 SCSI buses. I could not find any performance info related to this subject. Also, could not find much about chunk size. I did a simple dd test of these disks using a block size of 16, 32, 64, 128, 256, 512 and 1024K. 16 and 32K were best for overall speed and CPU usage. It got worse as the block size increased. I work with HP-UX systems alot. On HP systems, as block size increases CPU load decreases. But HP-UX has raw (character) devices. My dd test was with RedHat 8.0. Thanks for any info, Guy - 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
