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Re: KDE 4.2 requires local MySQL Server



Craig White wrote:
> well I haven't gotten there yet but 'they' do read...
> 
> http://techbase.kde.org/Projects/PIM/Akonadi#Deployment_issues

Well, none of the issues with NFS are unsurmountable:

> Multiple access: Should multiple Akonadi instances' mysqlds access a
> single set of data files the mysql will likely corrupt the data. This can
> happen in any NFS+YP installation where users can log onto any machine and
> access shared homes. MySQL relies on filesystem locking to prevent
> multiple access. MySQL multiple instance docu.

Should not be a problem if each user only runs Akonadi on one of the
machines sharing that volume at a time. Different users have different
Akonadi databases. And if your NFS installation has working locking, you
won't corrupt your data if you try, just fail to access it. (That said, NFS
locking tends to be broken one way or the other, so I'd suggest being
careful and not attempting to run Akonadi concurrently on multiple machines
for any given user.)

> InnoDB tables should not be used on NFS. 

This is pretty much the same as the above, only this time when the locking
is working as designed. From the given link:
> It is not a good idea to configure InnoDB to use datafiles or logfiles on
> NFS volumes. Otherwise, the files might be locked by other processes and
> become unavailable for use by MySQL.
Again, that shouldn't happen if you only run Akonadi on one of the machines
sharing that volume at a time, and you won't be affected by other users'
locks because the database is per user.

Pretty much the same kinds of corruption or lock contention would happen if
Akonadi was using flat files. Having processes on 2 computers manage the
same NFS-shared file is always a bad idea, with or without MySQL.

> NFS speed: MySQL documentation recommends against locating its data files
> on network shares.

That's a valid concern, but I don't think it will be that big a problem.

        Kevin Kofler


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