RE: OS400 DATA MIGRATION

yes and you have about 38 gb of data and programs.  You currently have 1
mirrored pair so you lose 4 gb in capacity for the backup drive.  You have a
RAID set containing 10 drives so you lose another drive to support that RAID
set - that amount of space is sued to store parity data.  Your effective
capacity is therefore 50.2 GB (4.19 times 12) minus 8.38 (4.19 times 2) or
41.9 gb.  Your system is 92 percent full so 41.9 times 0.92 = 38.54 gb.

Let's remove 2 drives from the 10 drive set.  That set will now have 8
physical drives but the space equal to one drive is reserved for parity
data.  8 drives minus 1 for the RAID parity data equals 7 drives.  7 drives
times 4.19 = 29.33 gb.  29.33 gb plus the mirrored drive (4.19 gb) equals
33.52 gb.  So after removing 8 gb from the RAID set, your system can contain
33.52 gb of data - just what you would have expected.  But, you have 38.54
gb of data.  Where will it go?  Well, it won't fit into 33.52 gb of space.

You could turn off RAID.  That would permit the space currently used for
parity storage to be used for data storage.  It would give you back one
drive.  33.52 plus 4.19 equals 37.71 gb.  Still not enough space to store
your 38.54 gb of data - and you are running your data in unprotected space.
In order to have enough space, you have to turn off RAID and mirroring and
run with a completely unprotected system.  You cannot just do this for the
time that it takes to clear the two drives then reinstall them as a mirrored
pair.

You have a problem that can be easily solved by backing up everything,
changing the disk subsystem and reinstalling everything.  That is probably
the fastest way to do this within the existing and new hardware.  If you
were to add a new disk IOP, you could add the new 8gb drives balance the
disk, then remove the 2 drives from the 10-drive raid set and make them into
a mirrored pair.  I suggest that this would be easier and safer and cheaper
than an unload-reload.

Richard Jackson
mailto:richardjackson@richardjackson.net
http://www.richardjacksonltd.com
Voice: 1 (303) 808-8058
Fax:   1 (303) 663-4325

-|-----Original Message-----
-|From: owner-midrange-l@midrange.com
-|[mailto:owner-midrange-l@midrange.com]On Behalf Of Oludare Ogunmadewa
-|Sent: Tuesday, October 10, 2000 4:15 PM
-|To: MIDRANGE-L@midrange.com
-|Subject: Re: OS400 DATA MIGRATION
-|
-|
-|Sorry guys,
-|
-|I've been tied up in meeting all day!
-|
-|Clarification:  I have 12 X 4 Gig and 1 of those is mirrored at
-|base for OS
-|and 10 is RAIDED.
-|
-|Dare
-|----- Original Message -----
-|From: "Richard Jackson" <richardjackson@richardjackson.net>
-|To: <MIDRANGE-L@midrange.com>
-|Sent: Monday, October 09, 2000 9:43 PM
-|Subject: RE: OS400 DATA MIGRATION
-|
-|
-|> Kewl!  I missed the part about how taking two drives out of the RAID set
-|> makes it too small to hold his data.  Turning off RAID will
-|give him 4 gb.
-|> But taking out two drives takes away 8 gb.  Using your number (38.5 gb
-|> instead of mine) it still doesn't work, he has to turn off RAID and
-|> mirroring to make room for the data.  A power failure while in this
-|> condition would be a most unwelcome event.  I see an
-|unload-reload in your
-|> future.
-|>
-|> Richard Jackson
-|> mailto:richardjackson@richardjackson.net
-|> http://www.richardjacksonltd.com
-|> Voice: 1 (303) 808-8058
-|> Fax:   1 (303) 663-4325
-|>
-|> -|-----Original Message-----
-|> -|From: owner-midrange-l@midrange.com
-|> -|[mailto:owner-midrange-l@midrange.com]On Behalf Of Larry Bolhuis
-|> -|Sent: Monday, October 09, 2000 6:56 PM
-|> -|To: MIDRANGE-L@midrange.com
-|> -|Subject: Re: OS400 DATA MIGRATION
-|> -|
-|> -|
-|> -|Dare,
-|> -|
-|> -|  To do this you need to go into DST, Work with DIsk Units, and remove
-|> -|the units in question from the ASP. You didn't specify but it sounds
-|> -|like you have a 5052 'top hat' with 10-4G drives and 6 open slots.
-|> -|Additionally it sounds like a mirrored pair of 4's in the
-|base unit. So
-|> -|if you are at 92% full now of a (calculated) 41.9G then you
-|have 38.58G
-|> -|of data. When you remove the 2 drives you will have only 33.52G of
-|> -|storage.  This means that in order to have enough space you
-|will need to
-|> -|remove Mirroring AND Stop Raid protection to have enough space to drop
-|> -|those drives without overflowing. Even then you will need to set your
-|> -|ASP storage limit to near 100% or DST won't let you do it. Being that
-|> -|full it'll take some time for sure! And of course if you lose a drive
-|> -|during that time, it's bye bye data!
-|> -|
-|> -|  So Dare, howz your tape drive working???  I think that in your
-|> -|situation I'd back up your entire system, clean the drive and repeat.
-|> -|Then I'd clear the data from ASP 1, Kill raid and mirroring,
-|remove the
-|> -|drives, do the hardware stuff, re-enable Raid, re-enable
-|Mirroring, add
-|> -|all the drives to the ASP and reload the system. You'll get a balanced
-|> -|load that way too.
-|> -|
-|> -|  My .02.
-|> -|
-|> -|  - Larry
-|> -|
-|> -|ps I haven't done one of these since, um, Saturday?
-|> -|
-|> -|> oludare wrote:
-|> -|>
-|> -|> Hi guys,
-|> -|>
-|> -|> I'm on V3R7M0 and running about 92% DASD usage.
-|> -|> What do I need to know to perform DATA MIGRATION. I need to perform
-|> -|> DATA MIGRATION before IBM CE come in for hardware upgrade.  I'm
-|> -|> planning DASD upgrade and need to remove 2 X 4gig old drive from a
-|> -|> RAID set then add
-|> -|> 7 X 8.58gig more to the raid set (Raid has 16 arms).  I need to get
-|> -|> all data on 2 old drive spread out on the remaining
-|> -|> 8 X 4gig before hardware upgrade by CE.  The 2 X 4gig DASD will be
-|> -|> added to bottom mirrored 2 X 4gig.  At the end I should have 8gig
-|> -|> Mirrored and a little above 92Gig on the Raided top 15 drives.
-|> -|+---
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