Hi, Glenn,

on Donnerstag, 03. Juni 2004 at 06:51 you wrote to amanda-users:

GE> Jon implied that hdparm may be just kidding about this. hdparm -Tt gives
GE> the following:

GE> ----
GE> /dev/hda:
GE>  Timing buffer-cache reads:   2800 MB in  2.00 seconds = 1399.51 MB/sec
GE>  Timing buffered disk reads:   82 MB in  3.00 seconds =  27.33 MB/sec
 
GE> /dev/hdc:
GE>  Timing buffer-cache reads:   2772 MB in  2.00 seconds = 1386.21 MB/sec
GE>  Timing buffered disk reads:  114 MB in  3.03 seconds =  37.62 MB/sec
GE> ----

GE> Since I have no feel for what pio would be like, I don't know. But the
GE> difference looks ballpark right for the different dma modes.

pio looks different ;-)
Would be much slower.

GE> I looked at another system: an old Dell server downstairs with a Maxtor
GE> PCI IDE card and a 2 or 3 year old Maxtor 60GB disk, also claiming to be
GE> udma5:

GE> ---- 
GE> /dev/hde:
GE>  Timing buffer-cache reads:   128 MB in  0.59 seconds =216.95 MB/sec
GE>  Timing buffered disk reads:  64 MB in  1.59 seconds = 40.25 MB/sec
GE> ---- 

GE> Something is wrong here. The disks up here are much newer, and a lot
GE> slower. I'm using the onboard controllers in an Intel D865GLC
GE> motherboard.

Getting away from AMANDA-topics:

You should get your IDE-setup straight.

A main point is the bus-mastering. It is also very important to
performance which device is the master and which is the slave on your
ide-bus.

You have hda and hdc here, which are the primary and secondary
master-drives on your first (only?) IDE-controller.

This is good so far, but you should also enable bus-mastering for you
controller.

Are there other drives at hdb and hdd ? Often these are used for
CD-ROM-drives.

If you REALLY want to get the best IDE-performance, don't use any
slave-drives. Put in a second IDE-controller (25 bucks maybe) and let
the faster controller control the disk drives as master drives.

One device per IDE-channel, so you would get maybe

hda        disk drive
hdc        disk drive
hde        cd-rom

no more slaves.

GE> Does anyone know of an equivalent to hdparm -Tt for SCSI disks?

Look at bonnie and bonnie++ maybe, they will test overall disk
performance.

-- 
best regards,
Stefan

Stefan G. Weichinger
mailto:monitor AT oops.co DOT at