[olug] Combining SDD and HDD drives?

[Dan Linder]

Interesting results.  If I read his notes correctly, the RAID-1 setup uses
the "write-mostly" flag to denote the two HDDs as being 'lesser' than the
SDD.

But since it's RAID 1, won't it be limited to the total size of the smallest
drive, namely the SDD?

Or did I overlook an option to the setup?

I wonder if ZFS or BTRFS have this as an option?

Dan

On Sat, Jul 10, 2010 at 20:35, Kevin D. Snodgrass <kdsnodgrass at yahoo.com>wrote:

> --- On Sat, 7/10/10, Dan Linder <dan at linder.org> wrote:
> > My current laptop has a 320GB 5400RPM
> > drive.  Space isn't an issue as much
> > as speed.   I've had 7200 RPM drives in the
> > past and while they are faster,
> > I can't justify the purchase of a new drive for a ~5-10%
> > speed-up in my
> > work.
> >
> > What I'd love is the 25-35% speed-up a SSD would provide
> > but a 320GB HDD
> > (even a 256GB) is out of my price range.  That got me
> > to thinking...
> >
> > My "working set" of these files are fairly small ~80GB, but
> > I can't split
> > the files across different filesystems for other reasons.
> >
> > If I could find a filesystem or multi-disk (MD) driver that
> > would allow for
> > multiple physical drives to be put into a pool, and then
> > the most used
> > sectors would be stored on the SSD while the rest would be
> > left on the HDD.
> >
> > I think this is a "hierarchial filesystem" idea, but I
> > can't find any notes
> > on how this might be setup for my situation.
> >
> > Any ideas?
>
> In comp.os.linux.setup, on July 5, 2010, "Arno" asked almost the exact
> question with Subj: RAID1: Read-prefer one disk?
>
> Looks like man mdadmin, and search for "--write-mostly", might be your
> answer...
>
> Arno posts results later under Subj: RAID1: HDD+SDD -- some benchmarks
>
> Kevin D. Snodgrass
>
>
>
>
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