Re: Unload/Reload

Minimum Drives for a Raid5 set is '3', but performance sucks and is much
better with 4 or more in the set.

On Tue, Sep 4, 2012 at 1:02 PM, Evan Harris <auctionitis@xxxxxxxxx> wrote:

I might be missing something but you need 4 disks minimum to make up a
RAID set - and in this situation its getting the first 4 that's an
issue.

By my calculation you have about 260 Gb free and you need to remove at
least 280gb free to remove 4 70's

If you're prepared to do an unload/reload then shutting down to a
restricted state and ending RAID before you remove the disks might be
something of a middle ground in terms of getting the job done.
I consider ending raid in this scenario less of a risk than doing an
unload reload but you might have a different view

- STRASPBAL to drain the first four disks your gonna pull
- Shut down to a restricted state
- End RAID
- Logically remove the first 4 disks (might need to restart to DST -
although it seems you can do this hot on 7,.1 going by Dr F's
comments)

With the additional 70Gb from ending raid and the temp storage going
down by being in a restricted state you might have enough head room to
pull 4 X 70's and replace with 4 X 280's

Once you've done the first 4 you can start RAID if you want to
minimize your exposure OR you could logically remove the remaining
drives and then add the rest of the 280;s

After that start RAID - across all 18 disks if you want, then do a
STRASPBAL to balance the system up.


On Wed, Sep 5, 2012 at 7:20 AM, DrFranken <midrange@xxxxxxxxxxxx> wrote:

18 is legal.

So thinking that way you drain one 70 (an 070 model) then exclude from
RAID, then insert a 140 then include it in RAID then add (and balance!)
to the ASP.

Lather Rinse Repeat. :-)

Once you're down to only the 70GB 074s drain them all, remove them then
add 140s two at a time. (IF you put in THREE or more it will demand you
start a new RAID set not add to the current set.) Since unit 1 (Load
Source) is already a 140 you're in a great spot to do this.

Would I do 18? We do it all the time in the SAS world but it means that
ANY two drive failure is fatal. What I might do is a 17 drive RAID set
with a hot spare.

Why not do RAID6? Well in your case (based ONLY on the tiny I/O numbers
you referenced earlier) I might like that idea. RAID6 would mean you can
lose TWO drives and still keep running. However you will need to STOP
RAID5 and then Start RAID6 to do that. With Hot Spare you just need to
have one UN-configured drive in a Load Source Capable slot to start Hot
Spare.

- Larry


On 9/4/2012 3:11 PM, rob@xxxxxxxxx wrote:

*This message was transferred with a trial version of CommuniGate(r)

Pro*

How many 140's can I have in one raid set? Is there a reason not to run
an 18 drive raid set of 140's?


Rob Berendt

--
Regards
Evan Harris
http://www.auctionitis.co.nz
--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list
To post a message email: MIDRANGE-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/midrange-l.

--
Kirk
--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list
To post a message email: MIDRANGE-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/midrange-l.