Re: RAID1 with multiple partitions
On Thu, Dec 16, 2010 at 12:44 PM, Bob Proulx <bob@proulx.com> wrote:
> Tom H wrote:
>> Bob Proulx wrote:
>>>
>>> I have not previously ever changed a hostname in /etc/mdadm/mdadm.conf
>>> and not had a problem renaming systems. My mdadm.conf files don't
>>> contain the actual hostname.
>>
>> Look up the HOSTNAME directive in the mdadm.conf man page.
>>
>> The default is "HOSTNAME <system>".
>
> Do you mean "HOMEHOST" instead of "HOSTNAME"?
>
> Regardless I have never changed it. My hostname is not "<system>".
> My mdadm.conf does not contain the actual hostname. And use of
> "<system>" is documented to automatically use the value from
> gethostname(2).
>
> In any case I have renamed systems many times and never had it fail
> because of changing the hostname nor have I ever seen the
> /dev/mdX_Y naming referred to in the documentation on any system that
> I have renamed. I wasn't even aware of the possibility until this
> discussion thread. When querying mdadm for details it is not
> reporting any arrays tagged with a homehost. I am using mdadm
> versions v2.6.7.2 in Lenny and v3.1.4 in Squeeze.
>
> I would guess that internally uuid naming has been doing the actual
> task of associating arrays. The documentation says:
>
> A new array will normally get a randomly assigned 128bit UUID
> which is very likely to be unique. ... Also, using --uuid=
> when creating a v0.90 array will silently override any
> --homehost= setting.
Yes, HOMEHOST, sorry.
Using "--uuid" overrides "--homehost" for metadata v0.90 since for
that version the hostname is used to create part of the uuid.
"<system>" means "use the hostname of the current box".
Both "mdadm --detail /dev/mdX" and "mdadm --examine /dev/sdXY" will
output "(local to host <hostname>)" on the uuid line for metadata
v0.90 and on the name line for metadata v1.x.
When you refer to "/dev/mdX_Y", do you mean partitionable arrays
(/dev/md/dX", "/dev/md/dXpY")?
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