Natively, Ontapp will always try to run in RAID level 4.
I.E if u have a volume of data disks and a spare disk, Ontapp will automatically get the spare disk as a Parity disk.
So imagine u have a shelf with 7 disk, u can't do best than a volume of 6 data disks and 1 parity disk. Netapp will refuse to use all disks as data.
 
But, in extreme cases, u should know that Ontapp is able to work in the degraded mode : without parity disk. But as u insert a spare disk, don't think u could had this disk as a data one because it would be automatically added as a parity one.
Just have a look at the "raid.timeout" option : by default, this value is set to 24. It means after 24 hours in degraded moide, the Filer just halt (to be sure to capt your attention).
Also, check for the "vol options vol0 raidsize value" and set it to the maximum (28) it means u can have one parity disk per 27 other data disks.
 
I think you could find a compromise in forgetting the spare disk but in leaving the parity disk : good performance and still an elementary security.
 
Here was the as-far-as I know.
----- Original Message -----
From: Jamey Maze
To: john@takedapharm.com ; tmerrill@mathworks.com ; listsarch-toasters@enteract.com
Cc: toasters@mathworks.com
Sent: Monday, October 15, 2001 10:38 PM
Subject: RE: F85 series

Filer volumes must have at least one data and one parity drive.
 
-----Original Message-----
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com]On Behalf Of john@takedapharm.com
Sent: Saturday, October 13, 2001 10:32 PM
To: tmerrill@mathworks.com; listsarch-toasters@enteract.com
Cc: toasters@mathworks.com
Subject: RE: F85 series

>[0] I know there are a lot of "configurations" (1 shelf, 2 shelves,
>etc.) but what I mean is if you buy one shelf, most people will, and
>NetApp recommends, keeping 1 disk as a parity drive and 1 as a hot
>spare.  Sure, one could create a RAID group with 7 data drives and no
>parity and hot spare, but I doubt that is "common."

Is it possible with ONTAP to create a volume without a parity disk?  I've got a bunch o' data that would function fine on a RAID-0 type volume... (SAS Tempfiles, holding tank for data transfers, etc...)

I didn't think it was possible... If it is, I've got a use for it.

-john

John Witham
Senior Data Networking Engineer
Takeda Pharmaceuticals North America, Inc.
V://847.383.3304
F://847.383.3205
mailto://jwitham@takedapharm.com


-----Original Message-----
From: Todd C. Merrill [mailto:tmerrill@mathworks.com]
Sent: Wednesday, February 21, 2001 2:44 PM
To: listsarch-toasters@enteract.com
Cc: 'toasters@mathworks.com'
Subject: RE: F85 series

On Tue, 20 Feb 2001, White, Lance wrote:

> performance...so, I ask again (hypothetically, that is), realistically, how
> SHOULD a vendor quote storage capacity?!?

        ...with the most common configuration [0], accepting
the default numbers and vendor's recommended operating configurations.
In NetApp's case, filers with shelves should be quoted retaining a
parity and hot spare drive with the default WAFL overheads and 20%
snapshot reserve.

        Think of it this way:  when a typical customer orders a filer
he opens it up, plugs it in, gives it a name and a few network numbers,
and <poof> how much space does he see?  *That* should be the number in
the quoted literature.

        Specifically, if we were considering the case of the
self-contained F85, this would be (6 drives minus 1 parity minus 1 hot
spare) 4 x 36 GB drives, minus ~10% filesystem minus ~20% snapshot
reserve, for a total usable space of roughly 100 GB.  In this way, there
is no suprise to the customer; management isn't upset that the "216 GB"
file server (36x6) they paid for is only giving them half of that to
use; etc.

        Vendors can say also there is a "maximum usable" configuration
available; "however, some important features may not be available in
this configuration.  Your SE can help you decide what is right for your
installation."  For instance, you could quote a "maximum usable" capacity
of 162 GB, which is 5 drives (sacrificing the hot spare) and no snapshot
reserve (5x36x0.9).

        All IMHO of course.

        I've got a small spreadsheet which takes the disk capacity and
number of drives and calculates this for me, 'cause I know the marketing
capacities are useless.


[0] I know there are a lot of "configurations" (1 shelf, 2 shelves,
etc.) but what I mean is if you buy one shelf, most people will, and
NetApp recommends, keeping 1 disk as a parity drive and 1 as a hot
spare.  Sure, one could create a RAID group with 7 data drives and no
parity and hot spare, but I doubt that is "common."

        Until next time...

The Mathworks, Inc.                             508-647-7000 x7792
3 Apple Hill Drive, Natick, MA 01760-2098       508-647-7001 FAX
tmerrill@mathworks.com                          http://www.mathworks.com
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