I want to congratulate a lot of Linux Software Raid folks. Really. I just set up a RAID 5 array on my Linux Machine (P4-3.06 Ghz -- Mandrake 9.2) using 5 External Firewire Drives. The performance is SO GOOD that I am able to write uncompressed 8-bit video files to my array through a Copper Gigabit network! That's a sustained 18 MB/sec -- going for 20 minutes straight. Under Windows 2000 using Veritas Volume Manger's RAID 5, I was barely able to sustain 4 MB/sec writing to the exact same drives -- even when I was writing directly from the Win 2000 server and not going through my network (Reading, however, was around 20 MB/sec). With Linux, I'm getting about 20 MB/sec through my TCP/IP network! And the Linux box isn't even struggling. Wow. I AM surprised by one thing, though. This is the second firewire array that I have put on my Linux machine. The first one was set up with 6 Firewire Drives that are bigger (200 GB versus 120 GB) and that have larger onboard cache (8 MB versus 2 MB). I set up those 6 drives as a RAID 10 array -- 3 mirrored pairs with a RAID 0 stripe on top of that. The performance I was able to achieve with the RAID 10 array was actually NO BETTER than what I am getting with RAID 5. Does that make sense? Should I be getting better (or at least equal) performance with RAID 5 compared to RAID 10? Shouldn't RAID 10 be faster both reading and writing? In both cases, I am using 128K chunk sizes, and the xfs filesystem with the maximum allowable Linux block size (4096) and an INTERNAL logfile. I would love to hear your comments. Andy Liebman - 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
