RE: New 270.

How do you check the Disk Arm Utilisation?  Is this the way the system
distributes data to the different disks?  If so is the impact on performance
the time it takes to move between disks if the system is distributing data
in a given way between smaller and higher capacity disks?

Sorry just a few basic questions from a beginner.  We have a variety of
different disk sizes and they all show equivalent % utilisation so how do we
know if the system is inefficient (apart from response time).  Response time
is okay but how do you know if it could be better?

-----Original Message-----
From: Chris Bipes [mailto:chris.bipes@cross-check.com]
Sent: 03 June 2002 22:29
To: 'midrange-l@midrange.com'
Subject: RE: New 270.


Our 720 has 16 4Gig drives + 5 8.5Gig drives.  They are equally loaded
percentage wise.  i.e. 76% used.  Due to the speed difference between the
old 4Gigers and the not so old 8.5Gigers, the smaller drives are being over
utilized while the bigger drives have less arm movement.  Huh??  Now that
the 8.5 & 17Gig drives have the same performance spec's, the 17Gig drives
would be worked harder cause they would serve us twice as much data.  That
is what will bite you.

Christopher K. Bipes          mailto:ChrisB@Cross-Check.com
Operations & Network Mgr  mailto:Chris_Bipes@Yahoo.com
CrossCheck, Inc.                http://www.cross-check.com
6119 State Farm Drive         Phone: 707 586-0551 x 1102
Rohnert Park CA  94928      Fax: 707 586-1884


-----Original Message-----
From: Andy Nolen-Parkhouse [mailto:aparkhouse@attbi.com]
Sent: Monday, June 03, 2002 1:16 PM
To: midrange-l@midrange.com
Subject: RE: New 270.


Philipp,

My recollections are different.  I don't have a system with different
sized drives in the same ASP so I can't check.  If I understand what
you're describing, then all drives should have the same amount of data
measured in GB.  My thought is that they would have the same per cent
utilization regardless of capacity.

Does anyone out there have a reasonably stable system with multiple
drive sizes in the same ASP?  What are the characteristics of the ASP?
Per cent utilization per drive as compared to per cent utilization of
the ASP as a whole?

Regards,
Andy Nolen-Parkhouse
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