Re: [Sheflug] UDMA-33 and cables.+hdparm

[Barrie Bremner <nospam [at] ecosse.net>]

Knickers indeed Chris :-)

[root@flux /root]# hdparm -Tt /dev/hda /dev/hdb

/dev/hda:
 Timing buffer-cache reads:   128 MB in  1.24 seconds =103.23 MB/sec
 Timing buffered disk reads:  64 MB in  5.20 seconds = 12.31 MB/sec

/dev/hdb:
 Timing buffer-cache reads:   128 MB in  1.24 seconds =103.23 MB/sec
 Timing buffered disk reads:  64 MB in  5.22 seconds = 12.26 MB/sec

Flux is running two newish Maxtor drives, 13.6 and 10Gb, noodles has
some old Samsung 320Mb on a buggy chipset...

[root@noodles /root]# hdparm -Tt /dev/hda

/dev/hda:
 Timing buffer-cache reads:   128 MB in  8.59 seconds = 14.90 MB/sec
 Timing buffered disk reads:  64 MB in 44.38 seconds =  1.44 MB/sec


For new drives try # hdparm -A1 -d1 -X66 -c3 -u1 /dev/hda

-X66 sets UDMA mode 2, d1 turns on DMA, c3 sets 32bit support, u1
unmasks IRQs apparently (don't ask me..it might make a small difference)
and A1 sets read-lookahead on.

 Check man hdparm for the lowdown, particularly on setting the various
(U)DMA and PIO modes.

 Still, I'd be interested to see what SCSI can do, especially since I'm
running an SMP system. Usually I'm waiting on the disks...

Baz.

Chris J/#6 wrote:
> 
> > i have two quantum drives and they produce (using hdparm -t) between 14 and
> > 17Mb/sec so yours are about right....... you have optimised them i take it?
> >
> 
> Hmm...knickers...
> 
>         [!%][infinitum][bin] >hdparm -t /dev/hdb5
>         /dev/hdb5:
>         Timing buffered disk reads:  32 MB in  5.80 seconds = 5.52 MB/sec
>         [!%][infinitum][bin] >
>         [!%][infinitum][bin] >hdparm -t /dev/hdc2
>         /dev/hdc2:
>         Timing buffered disk reads:  32 MB in  5.94 seconds = 5.39 MB/sec
>         [!%][infinitum][bin] >
> 
> Not too hot really :) Optimizaation is probably the area I'm least proficient
> in (HD performance is rarely an issue for me, so never bothered
> researching)... any tips? :) Dunno if its of any importance, but dmesg
> reports drives as follows:
> 
>         hda: FUJITSU MPA3035ATU, 3337MB w/0kB Cache, CHS=847/128/63, UDMA
>         hdb: Maxtor 90680D4, 6485MB w/256kB Cache, CHS=826/255/63, UDMA
>         hdc: Maxtor 92048D8, 19531MB w/1024kB Cache, CHS=39683/16/63, UDMA
> 
> Chris...

--
Barrie J. Bremner

Email:     TheEnglishman [at] ecosse.net
           (PGP public key available at pgp.mit.edu)

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