On 03/08/11 22:15, Gary R. Schmidt wrote:
> On Wed, March 9, 2011 12:22, Phil Stracchino wrote:
> [SNIP]
>> Now, I said I'd get back to the MySQL issues. I was reading through
>> some documents about mySQL on ZFS, and came across (again) a
>> recommendation from one MySQL tester that reported the best MySQL
>> performance from setting the InnoDB buffer pool small, 100MB or so, and
>> allowing ZFS to do the data caching. And I thought, "You know, I don't
>> believe I've ever tried this. I'll give it a shot and see how it goes."
>>
>> Well, after trying this, I can now definitively state: DO NOT DO THIS
>> IF YOUR BACULA CATALOG IS ON MYSQL. It may well work well for general
>> usage, but for Bacula, this configuration trick DOES NOT WORK. If you
>> are using Bacula with a MySQL catalog database on ZFS, configure MySQL
>> as you would if it were NOT on ZFS. Do NOT rely on the "let ZFS cache
>> the data" trick, because it won't work with Bacula.
>>
> Hmm, what version of MySQL did the document you found refer to? And what
> one are you using?
5.5, and 5.5, in both cases.
> It is possible that the recommendation is correct for the webstack or some
> internal SUN build of MySQL - my Webstack has "innodb_buffer_pool_size =
> 2048M" - perhaps it is correct when using the MyISAM engine? Or some such
> variant?
I'm using all InnoDB. There is almost no real-world case these days in
which MyISAM is the Right Engine.
> The only MySQL on ZFS recommendation I can remember reading was the one to
> change the record size of the underlying file system where the INNODB data
> files reside to 16K, nothing about buffer pool sizes.
Yup. zfs set recordsize. That comes in because innoDB writes in 16k chunks.
> That said, after far too many years writing, administering, and using
> databases, the thought of using a small buffer pool (or equivalent) on
> *any* database just doesn't feel right to me.
Same here. But I figured I'd try it once. NOT good at all.
--
Phil Stracchino, CDK#2 DoD#299792458 ICBM: 43.5607, -71.355
ala...@caerllewys.net ala...@metrocast.net p...@co.ordinate.org
Renaissance Man, Unix ronin, Perl hacker, SQL wrangler, Free Stater
It's not the years, it's the mileage.
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