5.0_BETA hangs

[Martti Kuparinen <martti.kuparinen%iki.fi@localhost>]

Hi,

I'm having problems with 5.0_BETA. If I trigger heavy disk I/O, e.g. remove 
/usr/src, the system still answers to ping and top keeps running on another 
xterm but nothing else works. And I can't Ctrl-C or Ctrl-Z the rm either.

I don't have a remove access card on that server so I can't get any kernel 
debugger output easily (other than with my cell phone's camera). Normal top 
shows just this:

load averages:  0.01,  0.02,  0.10;               up 0+00:28:14        14:33:49
41 processes: 40 sleeping, 1 on CPU
CPU states:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
Memory: 39M Act, 6572K Wired, 9496K Exec, 18M File, 800M Free
Swap: 4103M Total, 4103M Free

  PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU COMMAND
  883 martti    43    0   756K 1428K CPU        0:00  0.00%  0.00% top


dmesg:

aac0 at pci0 dev 5 function 0: Dell CERC SATA RAID 1.5/6ch
aac0: interrupting at ioapic1 pin 7
aac0: GETCOMMPREF appears untrustworthy.  Ignoring.
aac0: i80303 at 100MHz, 64MB mem (48MB cache), optional battery not installed
aac0: Kernel 4.1-0 [Build 7419], Monitor 4.1-0 [Build 7419], S/N C7DA99
aac0: Controller supports: 1097c<WCACHE,DATA64,HOSTTIME,RAID50,WINDOW4GB,SOFTERR
,ALARM>
ld0 at aac0 unit 0: RAID 1 (Mirror)
ld0: 931 GB, 121597 cyl, 255 head, 63 sec, 512 bytes/sect x 1953457408 sectors

fstab:

/dev/ld0a       /               ffs     rw              1 1
/dev/ld0b       none            swap    sw              0 0
/dev/ld0e       /backup         ffs     rw,log          1 2
kernfs          /kern           kernfs  rw              0 0
ptyfs           /dev/pts        ptyfs   rw              0 0
procfs          /proc           procfs  rw              0 0
tmpfs           /tmp            tmpfs   rw              0 0
/dev/cd0a       /cdrom          cd9660  ro,noauto       0 0

Any ideas? NetBSD/i386 3.0 was rock solid on this (with smaller HDDs).

Martti