PERC 6i and Incorrect drive size

[Elazar Broad]

Ah! Thanks Harald! Now let me ask you, does the SAS/5ir exhibit the 
same behavior?

Elazar

On Sun, 05 Oct 2008 18:26:13 +0000 Harald_Jensas at Dell.com wrote:
>Hi Patrick,
>
>You are seeing 512 MB less space available on each drive when 
>using the PERC controller. This is because the PERC Controller use 
>the DDF - Data Disk Format. 
>
>DDF is a SNIA standard on how data is formatted on RAID Disk 
>Groups. The standard specify that a minimum of 32 MB of space must 
>be reserved on each disk in the RAID Group for the DDF structure. 
>In the PERC case the designers decided to reserve 512 MB for the 
>DDF structure, on each disk in the RAID group. I am not sure why, 
>but I guess to be sure not to run out of space when new/more 
>features are added. Another reason to go for such a large space is 
>to make sure one can keep backward compatibility for a long 
>time... etc.
>
>
>You can read about DDF here:
>http://www.snia.org/tech_activities/standards/curr_standards/ddf/SN
>IA-DDFv1.2.pdf
>
>
>--
>Harald Jensås
>
>> -----Original Message-----
>> From: linux-poweredge-bounces at dell.com [mailto:linux-poweredge-
>> bounces at dell.com] On Behalf Of Elazar Broad
>> Sent: 05 October 2008 05:20
>> To: linux-poweredge-Lists; Boyd, Patrick
>> Subject: RE: PERC 6i and Incorrect drive size
>> 
>> Hi Patrick,
>>  Thanks for the reply. I am aware of that. My issue is more of 
>how
>> the PERC controller reports the drive size to the OS. Like so: 
>If I
>> plug one of the drives into the PowerEdge 1800's onboard CERC2/s
>> controller, fdisk reports the drive as having 
>640.1GB/1,250,263,728
>> sectors. On the other hand, fdisk on a PERC6i virtual 
>disk(RAID1)
>> reports 639.5GB/1,249,116,159 sectors. What I want to know is, 
>why
>> is there 500MB+ missing when using the PERC6i controller?
>> Additionally, on a clean install of VMWare's ESXi the included
>> partedUtil complains about the geometry reported by the
>> controller's BIOS.
>> 
>> Elazar
>> 
>> On Fri, 03 Oct 2008 13:35:48 +0000 Patrick_Boyd at Dell.com wrote:
>> >The drive manufactures measure drive size in base 10, i.e. a KB 
>is
>> >1000
>> >bytes, a MB is 1000 KB, and a GB is 1000 MB.
>> >
>> >Software measures drive size in base 2, i.e. a KB is 1024 
>bytes, a
>> >MB is
>> >1024 KB, and a GB is 1024 MB.
>> >
>> >That is the discrepancy that you are seeing.
>> >
>> >-----Original Message-----
>> >From: linux-poweredge-bounces at dell.com
>> >[mailto:linux-poweredge-bounces at dell.com] On Behalf Of Elazar
>> >Broad
>> >Sent: Friday, October 03, 2008 3:27 AM
>> >To: linux-poweredge-Lists
>> >Subject: PERC 6i and Incorrect drive size
>> >
>> >I know this is slightly off topic. I have a PERC 6i in a 
>PE1800, I
>> >
>> >have 2 WD 640GB drives connected to the controller. When 
>booting,
>> >if I hit Ctrl+R to access the configuration utility, both 
>drives
>> >only show as 609620MB as opposed to 640000. Any ideas are 
>greatly
>> >appreciated...
>> >
>> >Elazar
>> >
>> >--
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