[292] in linux-scsi channel archive
Slow SCSI - severe performance problems
daemon@ATHENA.MIT.EDU (Thomas Koenig)
Fri Jun 23 16:00:24 1995
To: linux-scsi@vger.rutgers.edu
Date: Fri, 23 Jun 1995 20:47:27 +0200 (MET DST)
From: Thomas.Koenig@ciw.uni-karlsruhe.de (Thomas Koenig)
We've recently bought an optical SCSI disk for backups (for Macs,
originally, but why not use it for Linux, as well?). This disk
is relatively slow, 550 kb/sec reading from the raw device.
We've got this device, a IBM 0632CHX (SCSI ID 4), hanging off a Seagate
ST31200N (SCSI ID 2), which in turn hangs off a NCR53c810.
When doing heavy disk I/O (such as writing a 60 - megabyte file and
rereading it, using iozone), the whole machine becomes very, very
sluggish whenever disk I/O is required; it locks up for minutes on end
until the iozone command is finished. Needless to say, this makes the
whole optical disk rather useless for day-to-day use.
Everything's deteced correctly at boot time.
Ideas?
--
Thomas Koenig, Thomas.Koenig@ciw.uni-karlsruhe.de, ig25@dkauni2.bitnet.
The joy of engineering is to find a straight line on a double
logarithmic diagram.
