Hi,
I'm preparing to upgrade my san to drbd9, but decided to test on VM's
first (smart idea).
I've proceeded up to this point in the manual:
http://drbd.linbit.com/users-guide-9.0/s-upgrading-drbd.html#s-upgrade-convert
This talks about upgrading the meta-data:
Now you need to convert the on-disk metadata to the new version; this
is really easy, it’s just running one command and acknowledging two
questions.
If you want to change the number of nodes, you should already have
increased the size of the lower level device, so that there is enough
space to store the additional bitmaps; in that case, you’d run the
command below with an additional argument |--max-peers=/<N>/|. When
determining the number of (possible) peers please take setups like the
Section 2.21, “DRBD client”
<http://drbd.linbit.com/users-guide-9.0/s-drbd-client.html> into account.
However, when I think, yes, that is a good idea, lets plan for the
future, and allow more peers, because I might want a 3rd copy of my
data, and/or I might use the DRBD "client". So I look in Section 2.21
which shows me how to prepare the config file, but I still need to
address the above problem "enough space to store the additional bitmaps".
Finally I find section 18.4 which references:
In the quick-sync bitmap, one bit represents a 4-KiB chunk of on-disk
data. If the bit is cleared, it means that the corresponding block is
still in sync with the peer node. That implies that the block has not
been written to since the time of disconnection. Conversely, if the
bit is set, it means that the block has been modified and needs to be
re-synchronized whenever the connection becomes available again.
So size of device divided by 4k divided by 8 should equal the size of
the bitmap in bytes, but I would assume there is some sort of header or
similar on this?
So, I'm clearly missing something in the documentation, and my google
fu, plus RTFM isn't working.
Can anyone advise the steps needed to "prepare" my LV which is currently
on-disk format v08 so that I can upgrade it to v09 with additional sync
nodes?
ie,
lvextend -L+xx /dev/vg0/drbdspace
How to calculate xx ?
drbdadm -v --max-peers=<N> create-md <resources>
If the size of the device has changed, will drbdadm still "find" the old
v08 signature that it needs to update? I think the DRBD signature is at
the end of the device, but now the end of the device has changed....
Also, I wasn't able to find much (any) information on how to migrate to
drbdmanage. It almost seems like it would be a completely manual
process, managing the old style config files manually, creating the new
drbdmanage based device, then migrate the data from the old to the new,
etc... Ideally, there would be some automated solution to import configs
and devices/etc, and have drbdmanage do the "conversion/migration" itself.
Finally, just how "stable/reliable" is v9? How do you use it, what
issues have you seen? Is it faster/slower or more stable/less stable etc
than v8.4?
Regards,
Adam
--
Adam Goryachev Website Managers www.websitemanagers.com.au
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