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To: Jason Thorpe <thorpej@nas.nasa.gov>
cc: "Kevin P. Neal" <kpneal@pobox.com>, hackers@freebsd.org,
        tech-kern@netbsd.org
Subject: Re: VPS mailing list, BSD interest? 
In-reply-to: Your message of "Tue, 01 Oct 1996 09:11:18 PDT."
             <199610011611.JAA00870@lestat.nas.nasa.gov> 
Date: Tue, 01 Oct 1996 12:43:23 -0700
From: James Graham <greywolf@siva.captech.com>
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Jason Thorpe sez:
# 
#  [Poul-Henning Camp sez]:
#  > There is no significant difference between the FDISK, bsd-disklabel,
#  > mirror, stripeing and raid 5 operations.  They all translate a
#  > (dev+blkno+len) tupple to one or more similar tupples.

1.  Minor nit:  (x+y+z) is a triple, not a tuple.

2.  There is no difference between the operations?  You've obviously
    not dealt with a RAID5 filesystem before.  Nice idea, but you pay
    for it with performance.  And yes, I consider performance significant.
    
The first time I ran the ccdconfig thing and tried to newfs it,
I ended up running it on unevenly sized filesystems (OK) with an
interleave of 1 (NOT OK!).  Boy, was THAT _slow_!  Not to mention
I wanted concatenation anyway... :-)

I haven't had the opportunity to stripe or mirror a filesystem yet
(insufficient disk space and differently-sized disks make this a
bit of a challenge), so I can't comment on performance.  But it's nice
to have the concatenation as when I partitioned my disks, I had one piddly
partition of 70MB left over.  Seeing as that wasn't really enough with
which to do jack, I concatenated it to my user disk.

# 
# Jason R. Thorpe                                       thorpej@nas.nasa.gov
# NASA Ames Research Center                               Home: 408.866.1912
# NAS: M/S 258-6                                          Work: 415.604.0935
# Moffett Field, CA 94035                                Pager: 415.428.6939

				--*greywolf;