[Linux-cluster] Linux clustering (one-node), GFS, iSCSI, clvmd (lock problem)

[Paul Risenhoover]

Gordan Bobic wrote:
> On Tue, 16 Oct 2007, Wendy Cheng wrote:
>
>>>  THOUGHTS:
>>>
>>>  I admit I don't know much about clustering, but from the evidence I 
>>> see,
>>>  the problem appears to be isolated to clvmd and iSCSI, if only for the
>>>  fact that my direct-attached clustered volumes don't exhibit the 
>>> symptoms.
>>
>> Will let LVM folks comment on rest of the issues. However, if you 
>> intend to use this as single node case, are you aware that both GFS 
>> and GFS2 support a "lock_nolock" protocol that doesn't require CLVMD 
>> ? It can be run on a plain storage device (say /dev/sda1)  and 
>> doesn't have any locking overhead. Do a "man gfs_mkfs" and search for 
>> "LockProtoName". A sample mkfs-mount command looks like the following:
>
> Err - possibly a misunderstanding, but GFS/GFS2 doesn't require 
> LVM/CLVM. You can run on a raw device without volume management.
Ouch.  Good to know.  If I use raw devices can I grow and shrink 
volumes?  The specific need is to be able to take a physical devices out 
of service (ie, one of my iSCSI devices) so that I can restripe it or 
replace it.

Here's another scenario: I've got two existing physical devices of ~3TB 
each, both are members of the nasvg_00 volume group (using clvmd), plus 
a third physical device that I'm trying to bring online.  Is there a 
migration path that allows me to format the new physical device with 
gfs/raw, join it to the exiting gfs file system, and then migrate the 
other physical devices (one by one) to a gfs/raw format? 

Oh and can anybody lend me a  tape backup system? ;)

>
> Gordan
>
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