[OmniOS-discuss] Warning that partition is too large when mirroring identical disks in root pool

Peter Tribble peter.tribble at gmail.com
Sat Feb 8 21:10:39 UTC 2014


On Sat, Feb 8, 2014 at 6:21 AM, Willard Korfhage <omniti at familyk.org> wrote:

>  That could happen, depending on how many bad blocks the disk has, but in
> this case, the numbers it reports, the numbers it says are inconsistent,
> are from the original OmniOS install. I am surprised that the original
> install would generate an inconsistent partition arrangement.
>

Why do you think that? What the error you've given is saying is that
the size of the Solaris partition on the new disk is smaller than the
size of the Solaris partition on the original disk. That's all.


> Now if I could just figure out how to format the disk, I could try
> starting from scratch. Given the Illumos bug, I suppose I'll have to pull
> it and format it on another machine.
>

I can't see where that bug comes into play. The need to do a low-level
format of a drive is extremely rare.

I see these discrepancies fairly frequently when fdisk gets out of whack.
Most commonly, because some drives have a diagnostic partition on them,
but sometimes because it can't decide whether to start at cylinder 0 or 1.
Or just because the drives were partitioned up on different OS versions.

Compare:

fdisk -W - /dev/rdsk/c2t0d0p0
fdisk -W - /dev/rdsk/c2t1d0p0

If the fdisk dimensions do actually match, then you could save
out the fdisk table off the first disk and load it onto the second,
something like:

fdisk -W /tmp/fmap /dev/rdsk/c2t0d0p0
fdisk -F /tmp/fmap /dev/rdsk/c2t1d0p0

and then do the ptrtvtoc|fmthard step.

If you look at the sizes reported, specifically:

*   32130 sectors/cylinder
*   60799 cylinders
*   60797 accessible cylinders

and

*                          First     Sector    Last
* Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
       0      2    00      32130 1953375480 1953407609
       2      5    01          0 1953471870 1953471869
       8      1    01          0     32130     32129

then it's allocated slice 0 up to the end of the 60797 accessible
cylinders, but slice 2 (which refers to the whole disk) is 64260
sectors or 2 cylinders longer, filling out to the end of 60799.
The second disk you have is reporting a size of 1953407610
sectors, or 0-1953407609, or 32130*60797, so it's just picked
up the accessible cylinders. The disks appear to be the same
size, it's those 2 inaccessible cylinders that are confusing matters.

If the fdisk dimensions are different (the second disk only appears
to really be 60797 sectors) then it's still not a problem, as all you're
interested in is slice 0, which is the right size. Simplest way to do
that is to grep out the line in the prtvtoc output for partition 2, and
fmthard will fill it in automatically at whatever size it thinks is correct.


On 2/7/2014 11:54 AM, Warren Marts wrote:
>
> This may be a genuine mismatch between the disks.
>
>  A few weeks ago I was trying to image between two apparently identical
> Western Digital RE2 400GB drives. They were produced on the same day and
> their serial numbers were only ~200 apart, but the disk utility reported
> block counts that differed by about 20,000 (10 MB) and neither count
> matched the one on the disk label.
>
>  I was surprised, to say the least.
>
>
> On Fri, Feb 7, 2014 at 10:14 AM, Willard Korfhage <omniti at familyk.org>wrote:
>
>> I just installed OmniOS r151008j last night, and today I wanted to mirror
>> rpool, but have a warning about the disk size. I have 2 Seagate 1TB disks
>> (model ST1000LM024HN), and my OmniOS install is on one of them. I told the
>> install to use the whole disk. Some version of OpenIndiana was previously
>> installed on the disk. The install went without any problem.
>>
>> c2t0d0 is the disk with OmniOS
>> c2t1d0 is supposed to be its mirror
>>
>> To do the mirroring, following the directions in the wiki, I did
>>
>> root at s1:~# pfexec fdisk -B c2t1d0p0
>> root at s1:~# pfexec prtvtoc /dev/rdsk/c2t0d0s2 | pfexec fmthard -s -
>> /dev/rdsk/c2t1d0s2
>> fmthard: Partition 2 specifies the full disk and is not equal
>> full size of disk. The full disk capacity is 1953407610 sectors.
>> fmthard: Partition 2 specified as 1953471870 sectors starting at 0
>>  does not fit. The full disk contains 1953407610 sectors.
>> fmthard: New volume table of contents now in place.
>>
>>
>> At this point I stopped, and haven't done the mirror.
>>
>> For the disk with the install, format reports
>>
>> Current Disk = c2t0d0
>> <ATA-ST1000LM024HN-M-0001 cyl 60797 alt 2 hd 255 sec 126>
>> /pci at 0,0/pci8086,1c02 at 1f,2/disk at 0,0
>>
>> and further information is
>>
>> root at s1:~# pfexec prtvtoc /dev/rdsk/c2t0d0s2
>> * /dev/rdsk/c2t0d0s2 partition map
>> *
>> * Dimensions:
>> *     512 bytes/sector
>> *     126 sectors/track
>> *     255 tracks/cylinder
>> *   32130 sectors/cylinder
>> *   60799 cylinders
>> *   60797 accessible cylinders
>> *
>> * Flags:
>> *   1: unmountable
>> *  10: read-only
>> *
>> * Unallocated space:
>> *       First     Sector    Last
>> *       Sector     Count    Sector
>> *           0     32130     32129
>> *
>> *                          First     Sector    Last
>> * Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
>>        0      2    00      32130 1953375480 1953407609
>>        2      5    01          0 1953471870 1953471869
>>        8      1    01          0     32130     32129
>>
>> Any idea what is going on?
>>
>> I tried to format the disk without the install (c2t1d0), just to start
>> with a completely fresh disk, but it doesn't work. This appears to be a
>> long-standing (11-month old) Illumos bug (
>> https://www.illumos.org/issues/3610)
>>
>>
>>
>> _______________________________________________
>> OmniOS-discuss mailing list
>> OmniOS-discuss at lists.omniti.com
>> http://lists.omniti.com/mailman/listinfo/omnios-discuss
>>
>
>
>
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-- 
-Peter Tribble
http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/
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