PERC 6i and Incorrect drive size

Mon Oct 6 11:29:59 CDT 2008

Disregard my last message, I was wrong. See 
http://support.dell.com/support/edocs/storage/RAID/PERC6ir/en/HTML/e
n/chapterb.htm. Well, that would explain it...

On Mon, 06 Oct 2008 15:30:25 +0000 Harald_Jensas at Dell.com wrote:
>Is moving drives with Virtual Disks configured between PERC and 
>SAS supported?
>That's news for me, is that documented anywhere?
> 
>--
>Harald
>
>________________________________
>
>From: Elazar Broad [mailto:elazar at hushmail.com]
>Sent: Mon 2008-10-06 16:59
>To: Jensas, Harald
>Cc: linux-poweredge-Lists
>Subject: RE: PERC 6i and Incorrect drive size
>
>
>
>So that would explain it. The VMWare tech that addressed my
>partition issue noted that 431MB was missing from the partition. 
>My
>RAID 1 array was originally on a SAS5/iR, I then moved it to a
>PERC6/i via the 'Import foreign configuration' option in the PERC
>BIOS. Is it safe to assume that the SAS5/iR uses about 80MB or so
>for configuration data where as the PERC6/i uses 512 as you
>previously stated? As far as I know, moving from a SAS5/iR to a
>PERC/6i is supported. Is the PERC controller supposed to rewrite
>the partition table?
>
>Thanks,
> Elazar
>
>On Mon, 06 Oct 2008 06:22:32 +0000 Harald_Jensas at Dell.com wrote:
>>Hi,
>>
>>No, most likely not.
>>
>>This is the info I could find:
>>
>>
>>SAS 5/iR - RAID Disk Data Format = LSI SSP
>>
>>PERC 5 - RAID Disk Data Format = Common DDF, Profile 1
>>PERC 6 - RAID Disk Data Format = Common DDF, Profile 1
>>
>>
>>As you can see the SAS 6/iR does not use DDF, so the SAS 5iR does
>>not exhibit the same behavior.
>>
>>
>>--
>>Harald Jensås
>>
>>
>>> -----Original Message-----
>>> From: Elazar Broad [mailto:elazar at hushmail.com]
>>> Sent: 05 October 2008 21:51
>>> To: Jensas, Harald
>>> Cc: linux-poweredge-Lists
>>> Subject: RE: PERC 6i and Incorrect drive size
>>>
>>> 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/
>S
>>N
>>> >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
>>> >> >
>>> >> >--
>>> >> >Financial aid not enough?  Click here for information on
>>> >funding
>>> >> >your
>>> >> >education.
>>> >>
>>>
>>>>http://tagline.hushmail.com/fc/Ioyw6h4fr47sgV1v2eLJxPb08J3E9nEuk
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>>j
>>> >F
>>> >> >U87Gn
>>> >> >wBUIotXmZhbFX/
>>> >> >
>>> >> >_______________________________________________
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