more RAM + faster disk -> slower box?!

Ian Pallfreeman ip at mcc.ac.uk
Thu Nov 29 12:34:38 GMT 2001


Reluctant as I am to admit it, this has got me beat. I'm getting nowhere with
either an explanation or a fix.

I have a news server (INN, trad spool) which recently lost a disk, part of
a mirrored pair holding all news stuff except the articles (i.e. binaries, 
history, active file, overview). The articles are on a RAB 3600 IDE<->SCSI
RAID, which, frankly, sucks, and has been the cause of much sorrow. The 
replacement disk is a SCSI 160MB/s, replacing an 80 -- same size, same 
geometry. And I took the opportunity to increase the memory from 256MB to
768MB, in the hope that this might further compensate for the bandwidth
problem in the IDE RAID. 

So: 80MB/s to 160MB/s, and 256MB to 768MB. Result? The damned thing is much,
much slower than it was. It could never keep up with my peer box (Diablo),
but by using multiple feeds I could usually get the important or popular
groups into it OK. Now it ain't catching up at all. 

Looking at ``systat -vm'' tells me none of the disks, even the poxy IDE
RAID where the articles live, is terribly busy (whereas I'd be seeing 
80-100% before the "upgrade"). The vinum-mirrored history/overview volume
is practically idle. The load average has gone up from 1-2 to 4-5, and
``top'' shows me far more processes in RUN state, and for far longer, 
than I'd expect:

55248 news      64   0  4060K  3592K RUN    112:47 80.03% 80.03% fastrm

I'm not used to seeing a ``fastrm'' burning CPU, even on old 50MHz Suns,
and it's been running for hours longer than normal. A quick ``truss''
shows me the expected calls to unlink(2), and nothing else.

Does anybody have any suggestions, please? Obviously I could remove some of
the RAM and see what happens, but that won't help me understand...

TIA,

Ian.

                              <---------->

Copyright (c) 1992-2001 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
	The Regents of the University of California. All rights reserved.
FreeBSD 4.4-STABLE #31: Mon Sep 24 16:32:29 BST 2001
    ip at karma:/usr/src/sys/compile/GODFREY
Timecounter "i8254"  frequency 1193182 Hz
Timecounter "TSC"  frequency 400910783 Hz
CPU: Pentium II/Pentium II Xeon/Celeron (400.91-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x652  Stepping = 2
  Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR>
real memory  = 805306368 (786432K bytes)
avail memory = 780464128 (762172K bytes)
Preloaded elf kernel "kernel" at 0xc02e4000.
Pentium Pro MTRR support enabled
Using $PIR table, 7 entries at 0xc00fdef0
npx0: <math processor> on motherboard
npx0: INT 16 interface
pcib0: <Intel 82443BX (440 BX) host to PCI bridge> on motherboard
pci0: <PCI bus> on pcib0
pcib1: <Intel 82443BX (440 BX) PCI-PCI (AGP) bridge> at device 1.0 on pci0
pci1: <PCI bus> on pcib1
pci1: <S3 Trio3D/2X graphics accelerator> at 0.0
isab0: <Intel 82371AB PCI to ISA bridge> at device 7.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel PIIX4 ATA33 controller> port 0xf000-0xf00f at device 7.1 on pci0
ata0: at 0x1f0 irq 14 on atapci0
ata1: at 0x170 irq 15 on atapci0
pci0: <Intel 82371AB/EB (PIIX4) USB controller> at 7.2
chip1: <Intel 82371AB Power management controller> port 0x5000-0x500f at device 7.3 on pci0
ahc0: <Adaptec 29160 Ultra160 SCSI adapter> port 0xe400-0xe4ff mem 0xef102000-0xef102fff irq 11 at device 16.0 on pci0
aic7892: Ultra160 Wide Channel A, SCSI Id=7, 32/255 SCBs
ahc1: <Adaptec 29160 Ultra160 SCSI adapter> port 0xe800-0xe8ff mem 0xef101000-0xef101fff irq 10 at device 17.0 on pci0
aic7892: Ultra160 Wide Channel A, SCSI Id=7, 32/255 SCBs
fxp0: <Intel Pro 10/100B/100+ Ethernet> port 0xec00-0xec3f mem 0xef000000-0xef0fffff,0xef100000-0xef100fff irq 12 at device 18.0 on pci0
fxp0: Ethernet address 00:d0:b7:09:0e:f9
inphy0: <i82555 10/100 media interface> on miibus0
inphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
orm0: <Option ROMs> at iomem 0xc0000-0xc7fff,0xd6000-0xd6fff on isa0
fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0
fdc0: FIFO enabled, 8 bytes threshold
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
sc0: <System console> on isa0
sc0: VGA <16 virtual consoles, flags=0x0>
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A, console
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0
ppc0: Generic chipset (NIBBLE-only) in COMPATIBLE mode
lpt0: <Printer> on ppbus0
lpt0: Interrupt-driven port
ad0: 4133MB <FUJITSU MPE3043AE> [8959/15/63] at ata0-master UDMA33
Waiting 5 seconds for SCSI devices to settle
da0 at ahc0 bus 0 target 0 lun 0
da0: <RAB 3600  > Fixed Direct Access SCSI-2 device 
da0: 40.000MB/s transfers (20.000MHz, offset 16, 16bit), Tagged Queueing Enabled
da0: 195400MB (400179200 512 byte sectors: 255H 63S/T 24910C)
da1 at ahc1 bus 0 target 0 lun 0
da1: <IBM DDYS-T18350N S96H> Fixed Direct Access SCSI-3 device 
da1: 160.000MB/s transfers (80.000MHz, offset 63, 16bit), Tagged Queueing Enabled
da1: 17501MB (35843670 512 byte sectors: 255H 63S/T 2231C)
da2 at ahc1 bus 0 target 1 lun 0
da2: <IBM DNES-318350W SAH0> Fixed Direct Access SCSI-3 device 
da2: 80.000MB/s transfers (40.000MHz, offset 30, 16bit), Tagged Queueing Enabled
da2: 17501MB (35843670 512 byte sectors: 255H 63S/T 2231C)
Mounting root from ufs:/dev/ad0s1a




More information about the Ukfreebsd mailing list