[olug] Combining SDD and HDD drives?

[Dan Linder]

On Sun, Jul 11, 2010 at 08:56, Kevin D. Snodgrass <kdsnodgrass at yahoo.com>wrote:

> > Or did I overlook an option to the setup?
> >
> > I wonder if ZFS or BTRFS have this as an option?
>
> Why?  If you use mdadm to set up a RAID1 you can format it with whatever
> filesystem you like.  XFS, btrfs, ext3/4, JFS, ZFS, etc...  The filesystem
> software won't even "know" about what happens "below" it.
>

If I remember ZFS (on Solaris at least), it handles both the filesystem
(ext/ext2/ext3/jfs/etc) functions and the multidisk (RAID, spares, etc)
internally.  I think you just run a command to add a new drive (HDD) and
then you can expand the ZFS partitions in smaller chunks.  If so, then the
system might have a similar "write-mostly" flag and/or an auto-tune feature
to mimic the hybrid HDD+SDD drive mentioned elsewhere.

I'll bounce this same question off a couple of of my companies ZFS expert -
they've played with ZFS a lot in lab and customer environments so they might
know if this is a feature or not.

Dan

-- 
***************** ************* *********** ******* ***** *** **
"Quis custodiet ipsos custodes?"
    (Who can watch the watchmen?)
    -- from the Satires of Juvenal
"I do not fear computers, I fear the lack of them."
    -- Isaac Asimov (Author)
** *** ***** ******* *********** ************* *****************