I tried it in VM on VirtualBox. Here is my output :
$ dd if=/dev/rwd0c of=/dev/null bs=1m count=10
10+0 records in
10+0 records out
10485760 bytes transferred in 0.403 secs (25985597 bytes/sec)
$
$ dd if=/dev/rwd0c of=/dev/null
^C18777+0 records in
18777+0 records out
9613824 bytes transferred in 8.291 secs (1159492 bytes/sec)
$
See difference in speed. So it looks like it's really good idea to use
bs and count options. Here are outputs from OpenSolaris in VM for
check :
1) with badly specified raw device
$ pfexec dd if=/dev/rdsk/c4d0p0 of=/dev/null bs=1M count=10
dd: reading `/dev/rdsk/c4d0p0': I/O error
3+0 records in
3+0 records out
3145728 bytes (3.1 MB) copied, 0.390689 s, 8.1 MB/s
2) with correct raw device
$ pfexec dd if=/dev/rdsk/c4d0s0 of=/dev/null bs=1M count=10
10+0 records in
10+0 records out
10485760 bytes (10 MB) copied, 0.153903 s, 68.1 MB/s
3) without bs and count options
$ pfexec dd if=/dev/rdsk/c4d0s0 of=/dev/null
^C12075+0 records in
12074+0 records out
6181888 bytes (6.2 MB) copied, 4.9814 s, 1.2 MB/s
On Thu, Dec 31, 2009 at 3:03 PM, Scott McEachern <sc...@erratic.ca> wrote:
> I've been using dd to test some of my hard drives and just ran into the
> oddest of coincidences.
>
> I used this command (or variation without the time command)
>
> # time dd if=/dev/rwd0c of=/dev/null
>
> on three machines with three HDD's of sizes 40GB SATA, 40GB IDE and 30GB
> IDE, one of those 40GB (SATA) drives was in my workstation. B The result is
> basically the same: x number of bytes transferred, etc. with no problems.
> B They are all a few years old. B I bought a brand-new Seagate Barracuda
> SATA/1.5TB/7200/32MB, installed it into my workstation and ran the same
test
> to get this:
>
> # dd if=/dev/rwd0c of=/dev/null B B B B dd: /dev/rwd0c: Input/output
error
> 268435455+0 records in
> 268435455+0 records out
> 137438952960 bytes transferred in 23763.827 secs (5783536 bytes/sec)
>
> What got me doing that in the first place was my workstation locking up
hard
> 3 times in the past few weeks. B I have no idea why, nothing in the system
> logs, etc, and the only change was the HDD. B I figured the drive was
> defective, ran the above test, and returned it for a replacement. B While
> there, I also picked up a WD 500GB SATA drive and installed that in my
> workstation (to be pre-built and installed in another PC), which gave this
> result:
>
> # time dd if=/dev/rwd0c of=/dev/null
> 976773168+0 records in
> 976773168+0 records out
> 500107862016 bytes transferred in 93283.067 secs (5361186 bytes/sec)
> 1554m43.06s real (etc)
>
> No I/O error, so it should be good. B That's 2 drives ok (40 and 500 GB)
and
> 1 drive bad in the same PC, now for the 2nd new 1.5TB drive:
>
> dd: /dev/rwd0c: Input/output error
> 268435455+0 records in
> 268435455+0 records out
> 137438952960 bytes transferred in 23740.766 secs (5789154 bytes/sec)
> 395m40.76s real (etc)
>
> Oh, another crappy drive, I guess I have bad luck. B Probably from a bad
> batch or something. B But wait...
>
> Look at the amounts transferred. B Exactly the same for both of the 1.5TB
> drives, and I assure you it's not accidentally the same drive, just the
> exact same make / model. B The cables / connections are good on known good
> hardware, plus two other different drives were fine. B It can't be some odd
> variable limit (or similar thing) because the 500GB values went well beyond
> where the 1.5TB drives crapped out.
>
> I don't believe it's the hardware (other than the drive), nor the software,
> but seeing those numbers being identical down to the byte is either
> incredibly coincidental or .. ? B I'm going to run the test again, but as
you
> can see from the time it won't be done for another 6.5 hours. B Betcha
it'll
> be the same.
>
> Can anyone think of a plausible explanation for this, other than maybe a
bad
> batch where the drives are all equally defective at the exact same spot?
> B While I'm here, can anyone recommend another tool than dd for testing
> drives? B Seems to me with those numbers, to finish a 1.5TB drive it'll
take
> around 76 hours. B I don't mind the time, I need thoroughness. B It's
better
> than having a workstation (or server) mysteriously lock up after the 30-day
> return/exchange is over.
>
> Just in case, here's a dmesg with some errors at the bottom regarding the
> drive.
>
> OpenBSD 4.6-stable (GENERIC.MP) #0: Sat Dec 26 23:19:02 EST 2009
> B r...@blackstaff.erratic.ca:/usr/src/sys/arch/i386/compile/GENERIC.MP
> cpu0: Intel(R) Pentium(R) 4 CPU 3.20GHz ("GenuineIntel" 686-class) 3.20 GHz
> cpu0:
>
FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUS
H,DS
>
,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,SBF,SSE3,MWAIT,DS-CPL,EST,CNXT-ID,CX16,xTPR
> real mem B = 1061974016 (1012MB)
> avail mem = 1018036224 (970MB)
> mainbus0 at root
> bios0 at mainbus0: AT/286+ BIOS, date 02/14/06, BIOS32 rev. 0 @ 0xfd61a,
> SMBIOS rev. 2.
> 34 @ 0xf0320 (59 entries)
> bios0: vendor IBM version "2EKT33AUS" date 02/14/2006
> bios0: IBM 8215W97
> acpi0 at bios0: rev 0
> acpi0: tables DSDT FACP TCPA MCFG APIC BOOT ASF! SSDT
> acpi0: wakeup devices AZAL(S3) EXP0(S5) EXP1(S5) USB1(S3) USB2(S3) USB3(S3)
> USB4(S3) US
> BE(S3) SLOT(S5) KBC_(S3) PSM_(S3) COMA(S5) COMB(S5)
> acpitimer0 at acpi0: 3579545 Hz, 24 bits
> acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
> cpu0 at mainbus0: apid 0 (boot processor)
> cpu0: apic clock running at 199MHz
> cpu1 at mainbus0: apid 1 (application processor)
> cpu1: Intel(R) Pentium(R) 4 CPU 3.20GHz ("GenuineIntel" 686-class) 3.20 GHz
> cpu1:
>
FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUS
H,DS
>
,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,SBF,SSE3,MWAIT,DS-CPL,EST,CNXT-ID,CX16,xTPR
> ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 24 pins
> acpiprt0 at acpi0: bus 0 (PCI0)
> acpiprt1 at acpi0: bus -1 (PEG_)
> acpiprt2 at acpi0: bus 2 (EXP0)
> acpiprt3 at acpi0: bus 4 (EXP1)
> acpiprt4 at acpi0: bus 10 (SLOT)
> acpicpu0 at acpi0: FVS, 1600, 1400 MHz
> acpicpu1 at acpi0: FVS, 1600, 1400 MHz
> acpitz0 at acpi0: critical temperature 255 degC
> acpibtn0 at acpi0: PWRB
> bios0: ROM list: 0xc0000/0xac00! 0xcb000/0x1000 0xcc000/0x1000
0xcd000/0x800
> 0xe0000/0x
> 1800!
> pci0 at mainbus0 bus 0: configuration mode 1 (bios)
> pchb0 at pci0 dev 0 function 0 "Intel 82945G Host" rev 0x02
> vga1 at pci0 dev 2 function 0 "Intel 82945G Video" rev 0x02
> wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
> wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
> intagp0 at vga1
> agp0 at intagp0: aperture at 0xc0000000, size 0x10000000
> inteldrm0 at vga1: apic 2 int 16 (irq 5)
> drm0 at inteldrm0
> "Intel 82945G Video" rev 0x02 at pci0 dev 2 function 1 not configured
> azalia0 at pci0 dev 27 function 0 "Intel 82801GB HD Audio" rev 0x01: apic 2
> int 22 (irq
> 9)
> azalia0: codecs: Analog Devices AD1981HD
> audio0 at azalia0
> ppb0 at pci0 dev 28 function 0 "Intel 82801GB PCIE" rev 0x01: apic 2 int 17
> (irq 11)
> pci1 at ppb0 bus 2
> em0 at pci1 dev 0 function 0 "Intel PRO/1000MT (82573E)" rev 0x03: apic 2
> int 16 (irq 5
> ), address 00:10:c6:b5:c1:72
> ppb1 at pci0 dev 28 function 1 "Intel 82801GB PCIE" rev 0x01: apic 2 int 16
> (irq 5)
> pci2 at ppb1 bus 4
> uhci0 at pci0 dev 29 function 0 "Intel 82801GB USB" rev 0x01: apic 2 int 23
> (irq 11)
> uhci1 at pci0 dev 29 function 1 "Intel 82801GB USB" rev 0x01: apic 2 int 19
> (irq 9)
> uhci2 at pci0 dev 29 function 2 "Intel 82801GB USB" rev 0x01: apic 2 int 18
> (irq 10)
> uhci3 at pci0 dev 29 function 3 "Intel 82801GB USB" rev 0x01: apic 2 int 16
> (irq 5)
> ehci0 at pci0 dev 29 function 7 "Intel 82801GB USB" rev 0x01: apic 2 int 23
> (irq 11)
> usb0 at ehci0: USB revision 2.0
> uhub0 at usb0 "Intel EHCI root hub" rev 2.00/1.00 addr 1
> ppb2 at pci0 dev 30 function 0 "Intel 82801BA Hub-to-PCI" rev 0xe1
> pci3 at ppb2 bus 10
> xl0 at pci3 dev 9 function 0 "3Com 3c905C 100Base-TX" rev 0x74: apic 2 int
> 21 (irq 7),
> address 00:01:02:3b:a6:d1
> bmtphy0 at xl0 phy 24: 3C905C internal PHY, rev. 6
> ichpcib0 at pci0 dev 31 function 0 "Intel 82801GB LPC" rev 0x01: PM
disabled
> pciide0 at pci0 dev 31 function 2 "Intel 82801GB SATA" rev 0x01: DMA,
> channel 0 wired t
> o compatibility, channel 1 wired to compatibility
> wd0 at pciide0 channel 0 drive 0: <ST31500341AS>
> wd0: 16-sector PIO, LBA48, 1430799MB, 2930277168 sectors
> wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 5
> atapiscsi0 at pciide0 channel 1 drive 0
> scsibus0 at atapiscsi0: 2 targets
> cd0 at scsibus0 targ 0 lun 0: <HL-DT-ST, DVDRAM GSA-4163B, AX13> ATAPI
> 5/cdrom removable
> cd0(pciide0:1:0): using PIO mode 4, Ultra-DMA mode 4
> ichiic0 at pci0 dev 31 function 3 "Intel 82801GB SMBus" rev 0x01: apic 2
int
> 19 (irq 9)
> iic0 at ichiic0
> adt0 at iic0 addr 0x2e: lm96000 rev 0x68
> spdmem0 at iic0 addr 0x50: 512MB DDR2 SDRAM non-parity PC2-4200CL5
> spdmem1 at iic0 addr 0x52: 512MB DDR2 SDRAM non-parity PC2-5300CL5
> usb1 at uhci0: USB revision 1.0
> uhub1 at usb1 "Intel UHCI root hub" rev 1.00/1.00 addr 1
> usb2 at uhci1: USB revision 1.0
> uhub2 at usb2 "Intel UHCI root hub" rev 1.00/1.00 addr 1
> usb3 at uhci2: USB revision 1.0
> uhub3 at usb3 "Intel UHCI root hub" rev 1.00/1.00 addr 1
> usb4 at uhci3: USB revision 1.0
> uhub4 at usb4 "Intel UHCI root hub" rev 1.00/1.00 addr 1
> isa0 at ichpcib0
> isadma0 at isa0
> com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
> com1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo
> pckbc0 at isa0 port 0x60/5
> pckbd0 at pckbc0 (kbd slot)
> pckbc0: using irq 1 for kbd slot
> wskbd0 at pckbd0: console keyboard, using wsdisplay0
> pcppi0 at isa0 port 0x61
> midi0 at pcppi0: <PC speaker>
> spkr0 at pcppi0
> npx0 at isa0 port 0xf0/16: reported by CPUID; using exception 16
> fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
> fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec
> mtrr: Pentium Pro MTRR support
> uhub5 at uhub4 port 1 "Dell Dell USB Keyboard Hub" rev 1.10/2.00 addr 2
> uhidev0 at uhub5 port 1 configuration 1 interface 0 "Dell Dell USB
Keyboard"
> rev 1.10/2
> .00 addr 3
> uhidev0: iclass 3/1
> ukbd0 at uhidev0: 8 modifier keys, 6 key codes
> wskbd1 at ukbd0 mux 1
> wskbd1: connecting to wsdisplay0
> uhidev1 at uhub5 port 1 configuration 1 interface 1 "Dell Dell USB
Keyboard"
> rev 1.10/2
> .00 addr 3
> uhidev1: iclass 3/0, 3 report ids
> uhid0 at uhidev1 reportid 1: input=1, output=0, feature=0
> uhid1 at uhidev1 reportid 2: input=1, output=0, feature=0
> uhid2 at uhidev1 reportid 3: input=3, output=0, feature=0
> uhidev2 at uhub4 port 2 configuration 1 interface 0 "Logitech USB Optical
> Mouse" rev 2.
> 00/43.01 addr 4
> uhidev2: iclass 3/1
> ums0 at uhidev2: 3 buttons, Z dir
> wsmouse0 at ums0 mux 0
> softraid0 at root
> root on wd0a swap on wd0b dump on wd0b
> wd0c: id not found reading fsbn 268435455 (wd0 bn 268435455; cn 16709 tn 85
> sn 15), ret
> rying
> wd0c: id not found reading fsbn 268435455 (wd0 bn 268435455; cn 16709 tn 85
> sn 15), ret
> rying
> wd0c: id not found reading fsbn 268435455 (wd0 bn 268435455; cn 16709 tn 85
> sn 15), ret
> rying
> wd0: transfer error, downgrading to Ultra-DMA mode 4
> wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 4
> wd0c: id not found reading fsbn 268435455 (wd0 bn 268435455; cn 16709 tn 85
> sn 15), ret
> rying
> wd0c: id not found reading fsbn 268435455 (wd0 bn 268435455; cn 16709 tn 85
> sn 15), ret
> rying
> wd0c: id not found reading fsbn 268435455 (wd0 bn 268435455; cn 16709 tn 85
> sn 15)
> (END)
>
>
> --
>
> -RSM
>
> http://www.erratic.ca
>
>
--
http://www.openbsd.org/lyrics.html
