[DRBD-user] Large discrepancies between non-DRBD and disconnected-DRBD on 0.7.22

Oliver Hookins oliver.hookins at anchor.com.au
Tue Jun 10 09:39:31 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Hi again,

I think at least part of my performance problem is that my al-extents is set
to 601 and the testing is writing out a file that is 8GB, which means lots
of metadata writes. I want to set the al-extents to a much larger value on
the live setup, but I can't find any information anywhere that says if you
can or cannot do this without restarting everything...

I've tried "drbdsetup /dev/drbd0 syncer --al-extents 3833" on my test setup
and it doesn't appear to break anything - in fact DRBD keeps running fine
even if I only set it on one node! What are the ramifications of changing
the al-extents on a live DRBD setup, and why can I change it on one node and
not the other (unless the node I set it on communicates the setting to the
other node...)

Oliver Hookins

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