SCSI Bus tuning.

[Gary Stanley]

Hiya.

With Adaptec 2120S Raid Controllers (PCI-X 66mhz) and 5 or 6 Ultra320 RAID5 
drives, what's the maximum data rate I could achieve on the array? It 
currently seems to max out around 30mbyte/s with a small amount of burst.

  procs      memory      page                    disks     faults      cpu
  r b w     avm    fre  flt  re  pi  po  fr  sr aa0 md0   in   sy  cs us sy id
  0 8 0  264040  75156   83   3   0   0 8321 8310   0   0 8251 23037 2613 
14 58 28
  6 2 0  265680  85652   80   0   0   0 8375 10985 651   0 8477 177349 3938 
14 62 24
  6 2 0  265780  95692   20   0   0   2 8419 11011 651   0 8426 201621 3493 
12 62 26

       tty           aacd0             acd0              fd0             cpu
  tin tout  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
    0    2  0.00   0  0.00   0.00   0  0.00   0.00   0  0.00  14  0 33 25 28
    0   77 51.71 637 32.18   0.00   0  0.00   0.00   0  0.00   7  0 26 24 43
    0   76 51.38 656 32.94   0.00   0  0.00   0.00   0  0.00   9  0 27 25 39
    0   76 51.85 616 31.18   0.00   0  0.00   0.00   0  0.00   8  0 26 26 39
    0   76 51.56 636 32.01   0.00   0  0.00   0.00   0  0.00   6  0 22 24 47

ITEM            SIZE     LIMIT    USED    FREE  REQUESTS

PIPE:            160,        0,      4,     98,    20542
SWAPMETA:        160,   233016,     19,     57,    12493
unpcb:           160,        0,     46,     54,    21349
ripcb:           192,   131070,      0,     42,        5
syncache:        160,    15359,      8,    273,  2099188
tcpcb:           576,   131070,   3956,   2664,  1970515
udpcb:           192,   131070,      6,     36,      243
socket:          192,   131070,   4008,   2690,  1992113
DIRHASH:        1024,        0,    471,    377,     3917
KNOTE:            64,        0,   6882,   2782,  3950885
NFSNODE:         352,        0,    647,    849,     2379
NFSMOUNT:        544,        0,      2,     12,        2
VNODE:           192,        0,  34216,     22,    34216
NAMEI:          1024,        0,      0,     32, 22168837
VMSPACE:         192,        0,     45,     83,    38265
PROC:            416,        0,     51,     47,    38271
DP fakepg:        64,        0,      0,      0,        0
PV ENTRY:         28,  2690702, 140870, 383281, 23461659
MAP ENTRY:        48,        0,   3633,   5760,  3394017
KMAP ENTRY:       48,    64455,    233,    151,    83750
MAP:             108,        0,      7,      3,        7
VM OBJECT:        92,        0,  32805,     99,   595113


If it helps any, Dual Xeon 2.0ghz procs, 2 gigs of ram, supermicro board, etc.