And here is exactly why I asked the question!
Good discussion. :)
I thought about putting it on a seperate partition, like Wvoice has, but
couldn't figure out why there would be a performance benefit. :)
On Thu, 2004-01-01 at 22:18, Jeremy Jackson wrote:
> Wvoice wrote:
> > Jerry,
> >
> > If you wish to avoid the recovery method, you can still use an external log
> > with your RAID. If you're using hardware RAID, where the array spans the
> > entire drive, create two partitions on the array (sda1 and sda2, where sda2
> > is used for the log and is less than 256MB). If you're using software raid,
> > then it's just as easy. Just create a couple of partitions on each drive in
> > the array. You'll then create an md1 stripe across one set of partitions
> > for data and another stripe (md2) on another set of partitions for metadata.
> >
> > You can then use the following: mkfs.xfs -l logdev=/dev/sda2,size=32000b
> > /dev/sda1. You can substitute md1 and md2 accordingly.
> >
> > It won't matter that you're creating a metadata device and a data device on
> > the same physical set of drives. You're still creating a new page buffer
> > for the new logical device and this is where you'll speed up performance.
> > The performance hit of physical disk seeks should be negligible. I've
> > actually benchmarked the difference between putting the journal on other
> > RAID stripes, other raids, fast disks, NVRAM, etc. You really shouldn't
> > notice much difference. Plus, placing the log on another stripe is pretty
> > cheap to do.
>
>
> How did you test this... lots of metadata writes? I can't believe this
> is a good idea for performance.
>
> Regards,
>
> Jeremy
--
Jerry Haltom <jhaltom@xxxxxxxxxxxxxxxxxxx>
Feedback Plus, Inc.
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