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My understanding was that Raid 0 (striping) increases read/write b/c it
alternates between 2 disks, it can write data faster than any one disk can
write, and the same goes for reading.
Raid 1 (mirroring) as you said, can increase read speed, but, it doesn't
speed up writing, as, it has to write the same data to 2 independent disks
at the same time. It does, however, add redundency (so, you have 2 disks
with the same data on them, one fails, you still have a full copy of your
data -- granted you have to do some restoring, but, you don't lose any
data -- this is what is important to some people). Then there are the
really weird ones, Raid 5 and 10. Raid 10 is a Raid 1 where each 'disk' is
in actuality a raid 0 disk. Raid 2 isn't used (I think) and Raid 3 and 5
have stuff to do with parity disks (a whole disk is set up for verifying
data in the case of 3, in 5 the parity is spread over various disks --
basically, faster than just 1 disk, but, has safety built in [at the cost of
a whole disk]).
I hope that makes sence.
-brad
---
Everybody loves to love you when you're far away -- Better than Ezra, At the
Stars
-----Original Message-----
From: plug-admin@lists.phillylinux.org
[mailto:plug-admin@lists.phillylinux.org]On Behalf Of Forge XP
Sent: Saturday, 1 June 2002 4:15 PM
To: plug@lists.phillylinux.org
Subject: Re: [PLUG] Linux Raid
----- Original Message -----
From: "Bill Jonas" <bill@billjonas.com>
To: <plug@lists.phillylinux.org>
Sent: Friday, May 31, 2002 12:56 PM
Subject: Re: [PLUG] Linux Raid
On Tue, May 28, 2002 at 11:02:46AM -0600, W. Chris Shank wrote:
> I still think that striping provides faster data writes. Mirroring will
> increase your read ability.
It's very possible I was wrong. I was going on what I had heard/read
somewhere and it's possible I could have gotten confused. (I meant to
add an "I am not a RAID expert but this is what I've heard" disclaimer
to the original message but forgot to do so.)
--
Bill Jonas * bill@billjonas.com * http://www.billjonas.com/
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." -- Benjamin Franklin
Mirroring occasionally decreases read/write latency, but only rarely, and
only on certain controllers. True hardware RAID controllers do offer both
greatly enhanced read and write speed, on striped array, but most (90%+)
'RAID' users are actually using a form of bootable software RAID, courtesy
of their Promise Fasttrak and HPT onboard controllers. There's nothing wrong
with these, I'm using a Fasttrak TX4 myself, but they should not be confused
with true hardware RAID.
Rich 'Forge' Mingin
www.tech-report.com
______________________________________________________________________
Philadelphia Linux Users Group - http://www.phillylinux.org
Announcements-http://lists.phillylinux.org/mail/listinfo/plug-announce
General Discussion - http://lists.phillylinux.org/mail/listinfo/plug
______________________________________________________________________
Philadelphia Linux Users Group - http://www.phillylinux.org
Announcements-http://lists.phillylinux.org/mail/listinfo/plug-announce
General Discussion - http://lists.phillylinux.org/mail/listinfo/plug
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