On 05-Apr-00 Paul Barton-Davis wrote:
> I've tried a variety of methods to measure the i/o performance I can
> get from 2 of my Ultra2 SCSI disks (Seagate Cheetah and a Quantum
> Viking II). I am hard pressed to get better than 17MB/sec from the
> Cheetah, and 10MB/sec from the Viking.
>
> I am aware that expecting the "80MB/sec" rate is not realistic, but
> these values seem absurdly low. I am trying to figure out why this
> should be happening. I did tests on entire disk partitions (/dev/sda,
> /dev/sdb) and on a newly created file in a newly created ext2
> filesystem.
according to seagate's online specifications for your drive:
http://www.seagate.com:80/support/disc/specs/scsi/st34502lw.html
the internal transfer rate is:
"INTERNAL TRANSFER RATE (mbits/sec)________152 to 231"
You probably have the small buffer disk (1024 byte vs 4096, which will make a
difference in short bursts but not for sustained thruput) - for sustained
thru put you will be limited by the rate that the data transfers to the media
(i.e. the internal transfer rate). Add to the the overhead of the protocol,
putting it on (or taking it off) the wire, seeks, etc, and your 17mbs ain't
looking so bad. In fact, it looks like you are actually achieving the internal
transfer rate, which is the absolute best you can physically, possibly do.
I didn't look up the Viking specs, but it would not surprise me if you
find something similiar...
-Greg
> --p
>
> Configuration:
> SuperMicro P6DBU mobo, w/Adaptec 7890 SCSI controller onboard
> dual PII-450
> Seagate Cheetah 4.5GB, 5.2ms 10000RPM
> Quantum Viking II 4.5GB, 7.5ms 10000RPM
>
> /proc/scsi/scsi:
>
> Attached devices:
> Host: scsi0 Channel: 00 Id: 00 Lun: 00
> Vendor: SEAGATE Model: ST34502LW Rev: 0005
> Type: Direct-Access ANSI SCSI revision: 02
> Host: scsi0 Channel: 00 Id: 01 Lun: 00
> Vendor: SONY Model: CD-ROM CDU-76S Rev: 1.1a
> Type: CD-ROM ANSI SCSI revision: 02
> Host: scsi0 Channel: 00 Id: 02 Lun: 00
> Vendor: QUANTUM Model: VIKING II 4.5WLS Rev: 5520
> Type: Direct-Access ANSI SCSI revision: 02
> Host: scsi0 Channel: 00 Id: 03 Lun: 00
> Vendor: YAMAHA Model: CRW4416S Rev: 1.0b
> Type: CD-ROM ANSI SCSI revision: 02
> Host: scsi0 Channel: 00 Id: 05 Lun: 00
> Vendor: Seagate Model: STT8000N Rev: 3.22
> Type: Sequential-Access ANSI SCSI revision: 02
>
> /proc/scsi/aic7xxx/0:
>
> Adaptec AIC7xxx driver version: 5.2.0/3.2.4
> Compile Options:
> TCQ Enabled By Default : Disabled
> AIC7XXX_PROC_STATS : Disabled
> AIC7XXX_RESET_DELAY : 5
>
> Adapter Configuration:
> SCSI Adapter: Adaptec AIC-7890/1 Ultra2 SCSI host adapter
> Ultra-2 LVD/SE Wide Controller at PCI 0/14/0
> PCI MMAPed I/O Base: 0xfebff000
> Adapter SEEPROM Config: SEEPROM found and used.
> Adaptec SCSI BIOS: Enabled
> IRQ: 10
> SCBs: Active 0, Max Active 2,
> Allocated 31, HW 32, Page 255
> Interrupts: 3478
> BIOS Control Word: 0x10a6
> Adapter Control Word: 0x1c5a
> Extended Translation: Enabled
> Disconnect Enable Flags: 0xffff
> Ultra Enable Flags: 0x0000
> Tag Queue Enable Flags: 0x0000
> Ordered Queue Tag Flags: 0x0000
> Default Tag Queue Depth: 8
> Tagged Queue By Device array for aic7xxx host instance 0:
> {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255}
> Actual queue depth per device for aic7xxx host instance 0:
> {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}
>
> Statistics:
>
> (scsi0:0:0:0)
> Device using Wide/Sync transfers at 80.0 MByte/sec, offset 15
> Transinfo settings: current(10/15/1/0), goal(10/127/1/0), user(10/127/1/0)
> Total transfers 2485 (1558 reads and 927 writes)
>
>
> (scsi0:0:1:0)
> Device using Narrow/Sync transfers at 5.0 MByte/sec, offset 15
> Transinfo settings: current(44/15/0/0), goal(10/127/0/0), user(10/127/1/0)
> Total transfers 0 (0 reads and 0 writes)
>
>
> (scsi0:0:2:0)
> Device using Wide/Sync transfers at 80.0 MByte/sec, offset 31
> Transinfo settings: current(10/31/1/0), goal(10/127/1/0), user(10/127/1/0)
> Total transfers 852 (815 reads and 37 writes)
>
>
> (scsi0:0:3:0)
> Device using Narrow/Sync transfers at 8.0 MByte/sec, offset 31
> Transinfo settings: current(30/31/0/0), goal(10/127/0/0), user(10/127/1/0)
> Total transfers 0 (0 reads and 0 writes)
>
>
> (scsi0:0:5:0)
> Device using Narrow/Sync transfers at 10.0 MByte/sec, offset 15
> Transinfo settings: current(25/15/0/0), goal(10/127/0/0), user(10/127/1/0)
> Total transfers 0 (0 reads and 0 writes)
>
>
> /proc/interrupts:
>
> CPU0 CPU1
> 0: 27921 16251 IO-APIC-edge timer
> 1: 2221 953 IO-APIC-edge keyboard
> 2: 0 0 XT-PIC cascade
> 4: 92 111 IO-APIC-edge serial
> 5: 0 1 IO-APIC-edge CS4232
> 10: 1740 1756 IO-APIC-level aic7xxx, RME Digi9652
> 11: 0 0 IO-APIC-level Trident 4DWave PCI
> 12: 382 3491 IO-APIC-edge PS/2 Mouse
> 13: 1 0 XT-PIC fpu
> 15: 59810 29798 IO-APIC-edge WaveFront - ICS2115/MIDI
> NMI: 44107 44107
> LOC: 44090 44089
> ERR: 0
>
> -
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----------------------------------
E-Mail: Gregory Hosler <gregory.hosler@eno.ericsson.se>
Date: 05-Apr-00
Time: 14:00:26
The answer to the meaning of life:
perl -e 'print$i=pack(c5,(41*2),sqrt(7056),(unpack(c,H)-2),oct(115),10); '
----------------------------------
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