Some more data, captured with "vmstat 2 10" during "mke2fs -j -E stride=16" (to match default chunk size of 64k). The disks are still WD RE2-GP 1TB. single disk (no stride): procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 1 2 0 1391888 546344 12784 0 0 527 3795 187 700 0 6 85 9 0 3 0 1260596 673608 12860 0 0 0 64816 402 136 0 7 0 93 0 3 0 1130200 800808 12836 0 0 0 56576 405 135 0 7 0 93 0 3 0 1007040 919952 12796 0 0 0 67108 405 149 0 7 0 93 0 3 0 892572 1030672 12852 0 0 0 54528 398 129 0 8 0 92 0 3 0 753968 1165840 12792 0 0 0 61696 404 145 0 12 0 88 0 3 0 631500 1284656 12788 0 0 0 61184 403 136 0 10 0 90 0 3 0 500448 1411856 12868 0 0 0 65536 404 139 0 10 0 90 0 3 0 382016 1526736 12860 0 0 0 59392 400 132 0 9 0 91 0 3 0 251276 1653840 12792 0 0 0 58880 403 138 0 11 0 89 RAID1 (2 disks, no stride): procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 1346104 586692 11716 0 0 524 3914 187 698 0 6 84 10 0 0 0 1236228 697284 11776 0 0 0 41452 568 2932 0 14 86 0 0 0 0 1130244 799684 11768 0 0 0 57518 670 2164 0 13 86 0 0 0 0 1013020 914200 11752 0 0 0 51870 637 1572 0 14 86 0 1 0 0 899232 1024972 11720 0 0 0 55504 632 2164 0 15 85 0 1 0 0 788188 1132912 11728 0 0 0 52908 643 1839 0 16 83 0 0 0 0 785120 1135564 11768 0 0 0 49980 660 2351 0 13 88 0 2 0 0 667624 1250252 11768 0 0 0 50028 671 2304 0 17 83 0 0 0 0 549556 1364940 11768 0 0 0 48186 651 2060 0 17 83 0 0 0 0 427292 1483724 11768 0 0 0 48568 711 3367 0 18 82 0 [progress of "writing inode tables" pauses regularly then increases in a burst] RAID0 (2 disks): procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 1 0 1333272 566348 10716 0 0 515 4452 188 708 0 6 84 10 0 2 0 1084244 808332 10632 0 0 0 123904 547 420 0 17 49 33 1 1 0 847580 1039004 10720 0 0 0 113228 539 498 0 18 50 32 1 1 0 603576 1276012 10724 0 0 0 119416 549 505 0 20 50 30 0 2 0 366996 1505836 10692 0 0 0 120636 544 499 0 19 50 31 1 1 0 113540 1751948 10700 0 0 0 116764 549 516 0 21 50 29 0 2 0 12820 1849320 10092 0 0 0 122852 544 637 0 21 50 29 0 2 0 11544 1850664 10160 0 0 0 120832 549 760 0 22 49 29 1 1 0 11892 1850312 9980 0 0 0 117996 539 732 0 22 48 30 0 2 0 12312 1849960 9980 0 0 0 107284 520 700 0 20 48 32 RAID1 (4 disks, no stride) procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 1701472 240556 11600 0 0 512 4653 189 706 0 6 84 10 0 0 0 1487172 453548 11580 0 0 0 26432 705 8308 0 15 85 0 2 0 0 1487804 453548 11580 0 0 0 28214 1122 2917 0 9 91 0 1 3 0 1309804 609292 11544 0 0 4 72986 1019 2111 0 21 78 1 3 0 0 1279008 626284 11584 0 0 0 63262 551 236 0 13 38 49 0 1 0 1294940 626284 11584 0 0 0 0 549 8816 0 8 49 43 0 0 0 1098588 831088 11596 0 0 0 6752 586 14067 0 13 78 8 0 0 0 1098672 831088 11584 0 0 0 33944 772 1183 0 9 91 0 0 0 0 981492 945776 11584 0 0 0 32974 841 4643 0 15 85 0 0 0 0 981436 945776 11584 0 0 0 30546 1120 2474 0 11 89 0 [extremely bursty, can't data be written to the disks in parallel?] RAID0 (4 disks): procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 1 2 0 945164 866516 11620 0 0 507 4675 190 707 0 6 84 10 0 1 0 633716 1169620 11528 0 0 0 151552 623 734 0 23 50 27 1 0 0 324452 1470016 11540 0 0 0 149504 622 717 0 24 50 26 1 0 0 14644 1771024 11540 0 0 0 149522 622 689 0 25 50 25 1 0 0 11948 1773160 11044 0 0 0 151552 621 992 0 28 48 24 1 1 0 12788 1772420 11156 0 0 0 151552 623 985 0 28 48 23 0 1 0 11952 1773060 11088 0 0 0 151552 622 1004 0 27 48 25 1 0 0 12744 1772220 11172 0 0 0 149504 620 1000 0 27 48 25 0 1 0 11888 1773192 11172 0 0 0 151552 622 967 0 28 47 25 0 1 0 12860 1773000 10268 0 0 0 151560 624 994 0 29 48 23 [there seems to be a cap when writing @~150MB/s, 4 single disks in parallel yield the same value. It's not the bus so it's probably the controller. Anyway I can live with that.] RAID5 (4 disks, syncing in b/g): procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 1223568 636836 11340 0 0 501 4748 190 702 0 6 84 10 0 0 0 1067636 788388 11372 0 0 0 63074 1639 19766 0 32 45 23 3 0 0 945316 907172 11276 0 0 0 63294 1684 20441 0 31 47 22 1 1 0 852584 997292 11340 0 0 0 57012 1651 15925 0 27 54 18 2 1 0 717548 1128364 11340 0 0 0 61824 1659 20125 0 31 46 23 0 0 0 586852 1255340 11340 0 0 0 60608 1643 14772 0 29 49 22 2 1 0 447692 1390508 11368 0 0 0 61400 1703 18710 0 31 43 26 3 0 0 333892 1501100 11340 0 0 0 64998 1769 20846 0 33 45 23 3 0 0 190696 1640364 11336 0 0 0 60992 1683 18032 0 32 48 20 0 1 0 110568 1718188 11340 0 0 0 59970 1651 13064 0 25 57 18 [burstier than RAID0 or the single disk but a lot smoother than RAID1. Keep in mind that it is syncing in parallel. NO responsiveness problem.] RAID5 (4 disks, --assume-clean): procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 5 2 0 11332 1814052 10536 0 0 472 4739 214 819 0 7 84 9 2 1 0 12304 1812828 10540 0 0 0 73586 1562 23273 0 38 41 20 0 0 0 13004 1812188 10584 0 0 0 69642 1649 19816 0 34 44 22 0 1 0 12188 1813084 10580 0 0 0 72452 1675 20730 0 37 42 21 2 0 0 11784 1813596 10540 0 0 0 74662 1776 20616 0 37 42 21 0 0 0 12348 1812956 10548 0 0 0 69546 1578 19984 0 32 47 21 2 1 0 11416 1813724 10608 0 0 0 71092 1712 20723 0 37 41 22 1 1 0 12496 1812880 10624 0 0 0 71368 1608 22813 0 38 42 20 2 0 0 11436 1813852 10628 0 0 0 74796 1727 22632 0 38 40 22 0 1 0 12552 1812572 10564 0 0 0 70248 1656 12608 0 33 48 19 Aside from the fact that RAID1 writes are somewhat erratic these values seem ok to me. I have no idea how fast a degraded 3/4 disk RAID5 array should be but it's still faster than a single disk. No responsiveness problems in any test. Is it possible that the Promise doesn't like the requests generated by the 1M chunk size used for the original setup? dmesg is silent so I guess I'll be doing chunksize tests this evening. Thanks, C. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
