TRIM or no TRIM?

[Steven Hartland]

----- Original Message ----- 
From: "Mark Felder"


> On Wed, Jul 24, 2013, at 10:13, Steven Hartland wrote:
>> 
>> gmirror may be another alternative that may correctly work with TRIM.
>> 
>> For reference correctly setup MySQL performance on ZFS works well for
>> use. Of particular interest is some of our data is highly compressible
>> making ZFS compression of particular benefit for our work load.
>> 
> 
> There are known interactivity issues with ZFS compression, so keep that
> in mind.

Some people have said that, we've never seen it here, quite the opposite
in fact.

> Also, you will want to make sure MySQL is on its own zfs filesystem and
> you may want to set primarycache=metadata so the database chooses what
> to keep in memory, not the filesystem. I ran a decent sized Postgres
> database of my own with compression and it was OK, but I didn't hit it
> very hard.

Depends on the setup, workload and available memory tbh I would use that
as a hard and fast rule.

    Regards
    Steve

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