Strange disk-write speeds

From: Richard B. Johnson (root@chaos.analogic.com)
Date: Thu Feb 14 2002 - 11:17:42 EST


Weird. I have two identical SCSI drives. They both synchronize
at 40 Mb/s on my Buslogic controller. They are the two ...
    Vendor: SEAGATE Model: ST318233LWV Rev: 0002
... drives shown below.

They both have ext2 file-systems occupying a single partition.
The time to write a file that fills up the file-system on the
"Id: 01" drive is about 1/2 an hour and the time to write a
file that fills up the file-system on "Id: 02" is about 1/2 day!

This is with the file created with "O_SYNC". If the file is
not created with "O_SYNC", there is no apparent difference in
write speed.

If I swap the jumpers on the two drives to isolate the drives
from the problem, the slooooo drive is the logical "ID: 02",
always... not the physical one!

Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: SEAGATE Model: ST32171W Rev: 0484
  Type: Direct-Access ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 01 Lun: 00
  Vendor: SEAGATE Model: ST318233LWV Rev: 0002
  Type: Direct-Access ANSI SCSI revision: 03
Host: scsi0 Channel: 00 Id: 02 Lun: 00
  Vendor: SEAGATE Model: ST318233LWV Rev: 0002
  Type: Direct-Access ANSI SCSI revision: 03
Host: scsi0 Channel: 00 Id: 04 Lun: 00
  Vendor: YAMAHA Model: CRW6416S Rev: 1.0b
  Type: CD-ROM ANSI SCSI revision: 02

`uname -a`
Linux chaos 2.4.1 #39 SMP Wed Jan 2 14:35:06 EST 2002 i686

Does anybody have a clue?

Cheers,
Dick Johnson

Penguin : Linux version 2.4.1 on an i686 machine (797.90 BogoMips).

    I was going to compile a list of innovations that could be
    attributed to Microsoft. Once I realized that Ctrl-Alt-Del
    was handled in the BIOS, I found that there aren't any.

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