Hi, I'm getting horrible performance on my samba server, and I am unsure of the cause after reading, benchmarking, and tuning. My server is a K6-500 with 43MB of RAM, standard x86 hardware. The OS is Slackware 10.0 w/ 2.6.7 kernel I've had similar problems with the 2.4.26 kernel. I've listed my partitions below, as well as the drive models. I have a linear RAID array as a single element of a RAID 5 array. The RAID 5 array is the array containing the fs being served by samba. I'm sure having one raid array built on another affects my I/O performance, as well as having root, swap, and a slice of that array all on one drive, however, I have taken this into account and still am unable to account for my machine's poor performance. All drives are on their own IDE channel, no master slave combos, as suggested in the RAID howto. To tune these drives, I use: hdparm -c3 -d1 -m16 -X68 -k1 -A1 -a128 -M128 -u1 /dev/hd[kigca] I have tried different values for -a. I use 128, because this corresponds closely with the 64k stripe of the raid 5 array. I ran hdparm -Tt on each individual drive as well as both of the raid arrays and included these numbers below. The numbers I got were pretty low for modern drives. In my dmesg, I'm seeing something strange.. I think this is determined by kernel internals. It seems strange and problematic to me. I believe this number is controller dependant, so I'm wondering if I have a controller issue here... hda: max request size: 128KiB hdc: max request size: 1024KiB hdg: max request size: 64KiB hdi: max request size: 128KiB hdk: max request size: 1024KiB I believe my hard drives are somehow not tuned properly due to the low hdparm numbers, especially hda and hdc. This is causing the raid array to perform poorly, in dbench and hdparm -tT. The fact that two drives on the same IDE controller are performing worse than the group, hda and hdc, further indicate that there may be a controller problem. I may try eliminating this controller and checking the results again. Also, I know that VIA chipsets, such as this MVP3, are known for poor PCI performance. I know that this is tweakable, and several programs exist for tweaking BIOS registers within Windows. How might I test the PCI bus to see if it is causing performance problems? Does anyone have any ideas on how to better tune these drives for more throughput? My partitions are: /dev/hda1 on / /dev/hda2 is swap /dev/hda3 is part of /dev/md0 /dev/hdi is part of /dev/md0 /dev/hdk is part of /dev/md0 /dev/md0 is a linear array. It is part of /dev/md1 /dev/hdg is part of /dev/md1 /dev/hdc is part of /dev/md1 /dev/md1 is a raid 5 array. hda: WD 400JB 40GB hdc: WD 2000JB 200GB hdg: WD 2000JB 200GB hdi: IBM 75 GXP 120GB hdk: WD 1200JB 120GB Controllers: hda-c: Onboard controller, VIA VT82C596B (rev 12) hdd-g: Silicon Image SiI 680 (rev 1) hdh-k: Promise PDC 20269 (rev 2) The results from hdparm -tT for each individual drive and each raid array are: /dev/hda: Timing buffer-cache reads: 212 MB in 2.02 seconds = 105.17 MB/sec Timing buffered disk reads: 42 MB in 3.07 seconds = 13.67 MB/sec /dev/hdc: Timing buffer-cache reads: 212 MB in 2.00 seconds = 105.80 MB/sec Timing buffered disk reads: 44 MB in 3.12 seconds = 14.10 MB/sec /dev/hdg: Timing buffer-cache reads: 212 MB in 2.02 seconds = 105.12 MB/sec Timing buffered disk reads: 68 MB in 3.04 seconds = 22.38 MB/sec /dev/hdi: Timing buffer-cache reads: 216 MB in 2.04 seconds = 106.05 MB/sec Timing buffered disk reads: 72 MB in 3.06 seconds = 23.53 MB/sec /dev/hdk: Timing buffer-cache reads: 212 MB in 2.01 seconds = 105.33 MB/sec Timing buffered disk reads: 66 MB in 3.05 seconds = 21.66 MB/sec /dev/md0: Timing buffer-cache reads: 212 MB in 2.01 seconds = 105.28 MB/sec Timing buffered disk reads: 70 MB in 3.07 seconds = 22.77 MB/sec /dev/md1: Timing buffer-cache reads: 212 MB in 2.03 seconds = 104.35 MB/sec Timing buffered disk reads: 50 MB in 3.03 seconds = 16.51 MB/sec The results from dbench 1 are: Throughput 19.0968 MB/sec 1 procs The results from tbench 1 are: Throughput 4.41996 MB/sec 1 procs I would appriciate any thoughts, leads, ideas, anything at all to point me in a direction here. Thanks, TJ Harrell - 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
