On Feb 4, 2008 4:49 PM, Ross S. W. Walker <rwalker@xxxxxxxxxxxxx> wrote:To move an external array to a new server is as easy as plugging
it in and importing the volume group (vgimport).
Typically I name my OS volume groups "CentOS" and give
semi-descriptive names to my external array volume groups, such
as "Exch-SQL" or "VM_Guests".
You could also have a hot server activate the volume group via
heartbeat if the first server goes down if your storage
allows multiple initiators to attach to it.I wish you luck here, but in my experience once an array is
> We are still checking with the vendor for a solution to move
> back to the 512 sectors rather than the 2k ones. Hopefully
> they come up with something.
created with a set sector size or chunk size, changing these
usually involves re-creating the array.
LVM might be able to handle the sector size though, no need to
create any partition on the disk, but future migration
compatibility could be questionable.
To create a VG out of it:
pvcreate /dev/sdb
then,
vgcreate "VG_Name" /dev/sdb
then,
lvcreate -L 4T -n "LV_Name" "VG_Name"
If you get a new external array say it's /dev/sdc and want to
move all data from the old one to the new one online and then
remove the old one.
pvcreate /dev/sdc
vgextend "VG_Name" /dev/sdc
pvmove /dev/sdb /dev/sdc
vgreduce "VG_Name" /dev/sdb
pvremove /dev/sdb
Then take /dev/sdb offline.
-Ross
PS You might want to remove any existing MBR/GPT stuff off of
/dev/sdb before you pvcreate it, with:
dd if=/dev/zero of=/dev/sdb bs=512 count=63
That will wipe the first track which should do it.
Luckily the array is empty at the moment as we are only at the phase of building/mounting so as it turns out there was a typo in the documentation and it is supposed to be created using the 16 byte CDB option and that will allow it use 512 sectors. (apparently there was a rogue not in the docs changing "If you have an LSI card you should use CDB" to "if you have an LSI card you should not use CDB") So this will be our next attempt and go from there.
Thank you very much for the help and the quick lesson on LVM. Neat stuff we will have to look at.
Rob
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