Software RAID issues (was Re: Suggestions solicited, server bring up)

[Alan Johnson]

On Mon, Nov 23, 2009 at 1:41 PM, Bill McGonigle <bill at bfccomputing.com>wrote:

> yeah, NFS and databases aren't really a great mapping - not enough
> semantics are supported even if they were fast enough.


But there is not a lot of meta data manipulation for DB files, mostly mtime
as I turn off atime by reflect these days.  I believe you, but I'll probably
do some testing on it to see if we can't get some of our less busy slave
data stores to live nicely in the cloud.


> Does your database
> support multi-level storage (e.g. putting your WAL or cache on your
> fastest drives)?


Well, it is MySQL/MyISAM, so not so much. (I know, I know.  Postgres/SQL is
where I'd like to be.)  We have played with ever break out of IO we can
squeeze out of it and even symlink busier tables over to faster storage
except on the one box we have with enough FusionIO to hold all the tables.
It is such a pile of hacks at this point, I can't understand why it has
taken this long for the bosses to each the change.  We are hiring 3-4 more
enegineers though, so maybe we'll have come cycles for Postgres/SQL next
year.


> FYI, ZFS supports this on the back-end (fast cache
> drives in front of cheaper slower drives.  But odds are NAS/SAN is slower
> than RAM on a local bus. :)
>

I know!  That's the primary cause of my cronic chin moisture.  This would
clean up a lot of the hacks I mentioned above for MySQL/MyISAM and make
everything else faster to boot.


>
> > What?! No. Oracle GPL'ing?  Really?  Got any articles handy were I can
> > read
> > up on the details. That's very exciting.
>
>   http://oss.oracle.com/projects/
>
> btrfs is already GPL, so I'm having trouble figuring out why they would
> insist on keeping ZFS CDDL.
>

Sweet.  I thought these guys were more evil than M$.  I'll check it out.
Thanks!
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