Re: hdparm

[Alexander <vulture@abac.com>]

Hi...

Umm:

/dev/hda:
 Timing buffer-cache reads:   64 MB in  1.61 seconds =39.75 MB/sec
 Timing buffered disk reads:  32 MB in  6.87 seconds = 4.66 MB/sec

Buffer-cache reads? Uh... explain that to me please, this particular UDMA
can't go past 33 MB/s.

But I do believe I heard of a UDMA/66 or something like that. I'm not
using that here, though, so...

Alex

On 17 Jul 1998, Gary L. Hennigan wrote:

> Date: 17 Jul 1998 12:33:09 -0600
> From: "Gary L. Hennigan" <glhenni@cs.sandia.gov>
> To: debian-user@lists.debian.org
> Subject: Re: hdparm
> Resent-Date: 17 Jul 1998 18:33:13 -0000
> Resent-From: debian-user@lists.debian.org
> Resent-cc: recipient list not shown: ;
> 
> <tko@westgac3.dragon.com> writes:
> | Martin Oldfield writes:
> | > 
> | > 
> | > I'd like to improve the IDE performance of my system. The IDE
> | > controllers are on a newish Intel motherboard; /proc/pci says:
> | > 
> | > IDE interface: Intel 82371AB 430TX PIIX4 (rev 1).
> | > 
> | > The drives are older:
> | > 
> | >  Model=QUANTUM FIREBALL ST6.4A, FwRev=A0F.0800, SerialNo=15672304
> | >  Model=QUANTUM FIREBALL_TM3840A, FwRev=A6B.1T00, SerialNo=39662361
> | >  Model=ST32140A, FwRev=08.08.01, SerialNo=JBF24417
> | >  Model=ST32140A, FwRev=08.08.01, SerialNo=JB770285
> | > 
> | > Can anyone suggest more aggressive (yet safe!) options for hdparm to
> | > make things run more quickly; alternatively is there a repository of
> | > known good settings.
> | 
> | Here's a script I added to /etc/init.d (with link in /etc/rc2.d) for better
> | performance. Use the '-i' option alone to find out the number for the '-m'
> | option. (man page explains all) This script is the last thing executed during
> | bootup. Enjoy! Oh BTW, my transfers jump from 5 Mb/sec to 35Mb/sec.
> 
> You're saying you get 35 mega Bytes per second? That seems highly
> unlikely!
> 
> I'm not disputing the fact that your script might improve performance,
> haven't tried it, but there's not a hard drive in existence, excluding
> specialty solid state drives and RAIDs, that can sustain 35MB/s (I'm
> assuming by Mb you meant Mega Bytes and not Mega bits, which is what
> Mb is generally used for?). Shoot, I don't even think the UDMA bus can
> acheive that? I believe it's theoretical maximum is 33MB/s. Whatever
> you're using to get this performance number isn't measuring your disk
> throughput but your cache performance.
> 
> Of course, if you meant what you wrote and get 35 mega bits/sec I
> could believe that, although if the drive was getting 5Mb/s to start
> with it's time for a new drive!
> 
> Try using
> 
> hdparam -t -T /dev/<whatever>
> 
> for a little better estimate.
> 
> Gary
> 
> 
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> 


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