On Sun, 7 Jan 2001, Tracy Di Marco White wrote:

# Date: Sun, 07 Jan 2001 14:19:09 CST
# From: Tracy Di Marco White <gendalia@iastate.edu>
# To: current-users@netbsd.org
# Subject: tape drive on siop causes pauses
# 
# 
# We've put two different tape drives on our 53c810, a DLT drive and a
# DAT drive.  Both of them cause the system to pause for seconds to minutes
# at a time when we're trying to do backups (using tar).  I assume this
# isn't normal, but I don't know if it's a driver problem or something
# else.
# 
# % cat /kern/version
# NetBSD 1.5Q (LYRA) #0: Sun Dec 31 22:52:32 CST 2000
#     root@solstice:/stuff/NetBSD/src/sys/arch/i386/compile/LYRA
# 
# siop0 at pci0 dev 11 function 0: Symbios Logic 53c810 (fast scsi)
# siop0: interrupting at irq 10
# scsibus1 at siop0: 8 targets, 8 luns per target
# scsibus1: waiting 2 seconds for devices to settle...
# st0 at scsibus1 target 6 lun 0: <SEAGATE, DAT    02779-XXX, 6280> SCSI2 1/sequential removable
# st0: siop0: target 6 asynchronous
# drive empty
# 
# The only reason for this scsi controller to exist on the machine it's on
# is to do backups, so this is problematic.  It's an add on card specifically
# for this motherboard (an ASUS P55T2P4 with the scsi bios built in), the
# card is the SC200.  It's the only motherboard we have this can go on, so
# we'd like to be able to use it, but if we can't make the pauses go away
# we'll replace it with an adaptec 1542 or some other spare adapter.  The
# machine is mostly doing nfs serving to NetBSD & Linux machines.
# 
# Complete dmesg:
# NetBSD 1.5Q (LYRA) #0: Sun Dec 31 22:52:32 CST 2000
#     root@solstice:/stuff/NetBSD/src/sys/arch/i386/compile/LYRA
# cpu0: AMD K6-2+/III+ (586-class), 451.03 MHz
# cpu0: features 8021bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8>
# cpu0: features 8021bf<PGE,MMX>
# total memory = 65152 KB
# avail memory = 57736 KB
# using 840 buffers containing 3360 KB of memory
# BIOS32 rev. 0 found at 0xf0400
# mainbus0 (root)
# pci0 at mainbus0 bus 0: configuration mode 1
# pci0: i/o space, memory space enabled
# pchb0 at pci0 dev 0 function 0
# pchb0: vendor 0x8086 product 0x1250 (rev. 0x03)
# pcib0 at pci0 dev 7 function 0
# pcib0: vendor 0x8086 product 0x7000 (rev. 0x01)
# pciide0 at pci0 dev 7 function 1: Intel 82371SB IDE Interface (PIIX3) (rev. 0x00)
# pciide0: bus-master DMA support present
# pciide0: primary channel wired to compatibility mode
# wd0 at pciide0 channel 0 drive 0: <Maxtor 90845D4>
# wd0: drive supports 16-sector PIO transfers, LBA addressing
# wd0: 8063 MB, 16383 cyl, 16 head, 63 sec, 512 bytes/sect x 16514064 sectors
# wd0: 32-bit data port
# wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 2 (Ultra/33)
# pciide0: primary channel interrupting at irq 14
# wd0(pciide0:0:0): using PIO mode 4, DMA mode 2 (using DMA data transfers)
# pciide0: secondary channel wired to compatibility mode
# pciide0: disabling secondary channel (no drives)
# vga1 at pci0 dev 9 function 0: vendor 0x1023 product 0x9660 (rev. 0xd3)
# wsdisplay0 at vga1: console (80x25, vt100 emulation)
# tlp0 at pci0 dev 10 function 0: DECchip 21140A Ethernet, pass 2.2
# tlp0: interrupting at irq 12
# tlp0: Ethernet address 00:40:05:a3:a1:43
# lxtphy0 at tlp0 phy 0: LXT970 10/100 media interface, rev. 0
# lxtphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
# siop0 at pci0 dev 11 function 0: Symbios Logic 53c810 (fast scsi)
# siop0: interrupting at irq 10
# scsibus1 at siop0: 8 targets, 8 luns per target
# bha0 at pci0 dev 12 function 0: BusLogic 9xxC SCSI
# bha0: interrupting at irq 11
# bha0: model BT-948, firmware 5.06J
# bha0: sync, parity
# bha0 targ 1: sync, offset 15, period 50nsec
# bha0 targ 2: sync, offset 15, period 50nsec
# bha0 targ 3: sync, offset 15, period 50nsec
# bha0 targ 4: sync, offset 15, period 50nsec
# bha0 targ 5: sync, offset 15, period 50nsec
# bha0 targ 6: sync, offset 15, period 50nsec
# scsibus0 at bha0: 8 targets, 8 luns per target
# isa0 at pcib0
# com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
# com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
# pckbc0 at isa0 port 0x60-0x64
# pckbd0 at pckbc0 (kbd slot)
# pckbc0: using irq 1 for kbd slot
# wskbd0 at pckbd0: console keyboard, using wsdisplay0
# lpt0 at isa0 port 0x378-0x37b irq 7
# pcppi0 at isa0 port 0x61
# spkr0 at pcppi0
# sysbeep0 at pcppi0
# isapnp0 at isa0 port 0x279: ISA Plug 'n Play device support
# npx0 at isa0 port 0xf0-0xff: using exception 16
# fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
# fd0 at fdc0 drive 0: 1.44MB, 80 cyl, 2 head, 18 sec
# isapnp0: no ISA Plug 'n Play devices found
# biomask ef65 netmask ff65 ttymask ffe7
# scsibus1: waiting 2 seconds for devices to settle...
# st0 at scsibus1 target 6 lun 0: <SEAGATE, DAT    02779-XXX, 6280> SCSI2 1/sequential removable
# st0: siop0: target 6 asynchronous
# drive empty

...I was going to comment about the bha0: targets 1-6 looking suspiciously
similar, but that's entirely possible given that you're running RAID :-).

Now, you said you had two tape drives?  Do you mean at the same time, or
do you swap between them?

If the former, I notice that st1 is conspicuously absent.

Do you have all your jumpers/switches on the tape drives set correctly?
Do you have tagged queueing/disconnect/reselect appropriately
{dis,en}abled in the flags on scsibus1?

# Tracy J. Di Marco White
# Project Vincent Systems Manager
# gendalia@iastate.edu

				--*greywolf;
--
*BSD: Where would you have rather been today, tomorrow?