2004-01-13 20:29:57

by Chris Friesen

[permalink] [raw]
Subject: Re: Proposed Enhancements to MD

Jeff Garzik wrote:
> Matt Domsch wrote:
>
>> I haven't seen the spec yet myself, but I'm lead to believe that
>> DDF allows for multiple logical drives to be created across a single
>> set of disks (e.g. a 10GB RAID1 LD and a 140GB RAID0 LD together on
>> two 80GB spindles), as well as whole disks be used. It has a

How is this different than the 20GB RAID0 and 6 15BB RAID1s that I've
got on two 100GB spindles right now?

I think its on 2.4, might even be 2.2.

Chris



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2004-01-13 20:36:34

by Matt Domsch

[permalink] [raw]
Subject: Re: Proposed Enhancements to MD

On Tue, Jan 13, 2004 at 03:29:45PM -0500, Chris Friesen wrote:
> How is this different than the 20GB RAID0 and 6 15BB RAID1s that I've
> got on two 100GB spindles right now?

Indeed, md does this with partitions on the disks today, so it is
analogous; DDF does this with disk extents, which has the same
functionality as partitions, but without an MSDOS partition table to
define the partitions, but an on-disk metadata format (yes, partition
tables are metadata too...).

The solution needs partitions/extents in two places.
1) below the logical drive, from which logical drives are created.
2) above the logical drive, on which multiple file systems are
created.

md provides 1) today, and as discussed today patches exist to do 2)
that have not yet been merged.


--
Matt Domsch
Sr. Software Engineer, Lead Engineer
Dell Linux Solutions http://www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com