[dba-Tech] Performance in disc partitions

Erwin Craps - IT Helps Erwin.Craps at ithelps.eu
Mon Jan 28 10:49:52 CST 2008


I personally would never use an onboard raid to store data.

If U use a removable controller you can swap controller and disks to
another system when your system is defect.
Doing so you have your data back in a few minutes...

Since the OS is pretty much system depending, you could use the onboard
raid only for your OS disk.

Erwin




-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of DJK(John)
Robinson
Sent: Monday, January 28, 2008 5:38 PM
To: 'Discussion of Hardware and Software issues'
Subject: Re: [dba-Tech] Performance in disc partitions

All my discs seem just fine, and have just been thrashed by PassMark's
Performance Test.  HD Tune (v2.54) never gets to the stage of looking at
them, as far as I can tell.  (Tried re-installing:  no difference.)
Maybe
another day, another system.

Thanks anyway
John


-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Erwin Craps
- IT
Helps
Sent: 28 January 2008 15:47
To: Discussion of Hardware and Software issues
Subject: Re: [dba-Tech] Performance in disc partitions


Hummm, never had any problem with HD Tune on any system I ever used it.

Maybe you have a disk prob?

-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of DJK(John)
Robinson
Sent: Monday, January 28, 2008 3:08 PM
To: 'Discussion of Hardware and Software issues'
Subject: Re: [dba-Tech] Performance in disc partitions

Hi Erwin

I tried HDtune, but it spends most of its time Not Responding so I've
binned
it.  May be something to do with my system, of course.

John


-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Erwin Craps
- IT
Helps
Sent: 28 January 2008 10:18
To: Discussion of Hardware and Software issues
Subject: Re: [dba-Tech] Performance in disc partitions


The edge of the disk also means lower access times.
I don't know why because RPM is the same at the inner as outer side of
the
disk.

I know that CD drives change their RPM speed depending how far they are
on
the inner and outer side of a cd so the laser can keep up reading the
data,
don't know if that is true for HD. That could be an explanation for
lower
access times, because it takes longer for the data to pass the head.


You can check http://www.hdtune.com/ it's a free disk performance check,
it
will show you the transfer rate / access time for your disk over the
whole
disk.

Erwin




-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of DJK(John)
Robinson
Sent: Monday, January 28, 2008 10:34 AM
To: 'Discussion of Hardware and Software issues'
Subject: Re: [dba-Tech] Performance in disc partitions

Thanks, John.  That would suggest higher transfer rates nearer the edge,
with some cylinders holding more than others.

Has anyone got any good links to this sort of stuff?

Oh, and of course I'm still interested in knowing whether the 'first'
partition is nearer the edge or the spindle...

John


-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of jwcolby
Sent: 28 January 2008 00:57
To: 'Discussion of Hardware and Software issues'
Subject: Re: [dba-Tech] Performance in disc partitions


IIRC, the disk controller speeds up the writes as the tracks move
outwards
towards the edge of the platter.  IOW there is more surface area on the
outer tracks so they just bump up the waveform to allow more data to be
written in that larger surface area.  When thought of from that
perspective,
the outer tracks hold more data / track and so may require less head
movement. I have no idea whether the first volume is on the inner tracks
or
the outer tracks.


John W. Colby
Colby Consulting
www.ColbyConsulting.com 
-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of DJK(John)
Robinson
Sent: Sunday, January 27, 2008 7:47 PM
To: 'Discussion of Hardware and Software issues'
Subject: [dba-Tech] Performance in disc partitions

I am about to partition a new disc.  One partition will be very active
in
terms of reads and writes, another almost dormant.

Is there any advantage in performance terms in having the active
partition
as the 'first' one on the disc?  Or the last one?

It's a long time since I was involved in disc layout at a low level, and
I'm
wondering whether 'cylinders' these days are still all the same size,
with
the data near the edge of the platter just more spread out than that
near
the spindle - or not?

TIA
John


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