Bug in aac?

[Cstdenis]

I am running 6.1-p11 with a Adaptec SAS RAID 4800SAS running a mirror of 
2 15k rpm SCSI drives.

Under heavy IO load (Its a database server) I get the following 
accompanied by serious system lag:

Jan  9 20:52:42 ayu kernel: aac0: COMMAND 0xc8f56f80 TIMEOUT AFTER 34 
SECONDS
Jan  9 20:52:42 ayu kernel: aac0: COMMAND 0xc8f54f00 TIMEOUT AFTER 34 
SECONDS
Jan  9 20:52:42 ayu kernel: aac0: COMMAND 0xc8f56b40 TIMEOUT AFTER 34 
SECONDS
Jan  9 20:52:42 ayu kernel: aac0: COMMAND 0xc
Jan  9 20:52:43 ayu kernel: 8f56740 TIMEOUT AFTER 34 SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f57640 TIMEOUT AFTER 34 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f58440 TIMEOUT AFTER 34 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f57bc0 TIMEOUT AFTER 34 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f59b40 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f57c80 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f59600 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f5a0c0 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f58c00 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f55f40 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f580c0 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f53280 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f58bc0 TIMEOUT AFTER 35 
SECONDS
Jan  9 20:52:43 ayu kernel: aac0: COMMAND 0xc8f59940 TIMEOUT AFTER 35 
SECONDS

(hex after command and number of seconds varies)

Excerpts from dmesg
-------------------

FreeBSD 6.1-RELEASE-p11 #0: Wed Jan  3 19:06:12 CST 2007
    root at ayu.ctgameinfo.com:/usr/obj/usr/src/sys/AYU
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel(R) Xeon(R) CPU            3060  @ 2.40GHz (2394.01-MHz 
686-class CPU)
  Origin = "GenuineIntel"  Id = 0x6f6  Stepping = 6
  
Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0xe3bd<SSE3,RSVD2,MON,DS_CPL,VMX,EST,TM2,<b9>,CX16,<b14>,<b15>>
  AMD Features=0x20100000<NX,LM>
  AMD Features2=0x1<LAHF>
  Cores per package: 2
real memory  = 3622699008 (3454 MB)
avail memory = 3545722880 (3381 MB)
<snip>
aac0: <Adaptec SAS RAID 4800SAS> mem 
0xd8400000-0xd85fffff,0xd8200000-0xd83fffff,0xe0000000-0xe7ffffff irq 26 
at device 14.0 on pci11
aac0: New comm. interface enabled
aac0: Adaptec Raid Controller 2.0.0-1
<snip>
aacd0: <RAID 1 (Mirror)> on aac0
aacd0: 69988MB (143335424 sectors)


The problem happens a few times a day each time lasting only a matter of 
minutes.


I searched the mailing lists for other having this problem, but all I 
found were older ones from early 5.x that are supposed to be fixed now.