It just begs the question everywhere: how to move a journaling log to a new device?

[Laurent Imbaud <laurent@xxxxxxxxx>]

Hello,

First, thank you for your excellent software and documentation.

I have poured over the white paper, the docs, read the man pages several 
times and I think I understand well enough what the issues and 
possibilities are.

But I see nowhere a single way of moving the log, say to an external 
device if disk seek is suspected to be a performance issue, short of
backing up the data, doing a new mkfs.xfs and copying back.

I tried using the logdev option of mount in the hope that the location 
could be moved at that point but that was not accepted, given the xfs 
was created with an internal log.

On a related issue, some idea of how big the log should be would be
worth documenting more precisely.  mkfs.xfs complained the logdev 
partition was too big in one manipulation, stating a maximum of 12k 
blocks (forgive me if this is not entirely accurate, I did not write 
down the exact message).

It would seem simple, convenient and desirable for administrators to 
move the location of the log at anytime, even, while the system is 
mounted.  Solid state disks come cheap nowadays and would make great
log devices, especially if one could point and xfs to log there after it 
has been in production for a while.

I would appreciate very much hearing what you think.  Hopefully, I have 
simply missed an obvious thing somewhere.

Thank you.


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| Laurent Imbaud,          |     laurent@xxxxxxxxxxxxxxxxx   |
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