I’ve read this and
other similar documents, but it doesn’t really answer my specific
question. Basically:
Company purchases filer
with 4 full shelves of 14 disks.
Netapp recommends
16-disk raid groups at install time.
Aggregate is created
using 3 full raid groups of 16 disks, per best practices recommendations of
adding full raid groups
Filer is left with 8
spares (not 7 as I incorrectly mentioned before)
My options at this
point seem to be: 1) add another raid group of 6 disks or 2) leave 8
spares until some future time when capital budgets may purchase more
shelves. I don’t think increasing the raid group size is an option as I
don’t believe you can increase the size of existing already-full raid
groups?
Anyway, it feels like a
big waste to me to have 8 hot spares, but if the performance or reliability
costs of a 6 disk RAID-DP group are too large I can live with
it.
--
Michael W. Sphar -
IS&T - Lead Systems Administrator
SMBU Engineering
Support Services, BMC Software
From: Parisi,
Justin [mailto:Justin.Parisi@netapp.com]
Sent: Monday, March 19, 2007 3:01
PM
To: Jason Herring;
Subject: RE: FAS3020 - aggr best
practises.
Here's a good document
to browse over for this particular issue...
http://www.netapp.com/library/tr/3437.pdf
From:
owner-
Sent: Monday, March 19,
2007 3:08 PM
To:
Subject: RE: FAS3020 - aggr best
practises.
You can always
go with a larger RAID group size - it does support up to 28. However, at
some point you have to bite the bullet and lose 2 more disks to parity. It
depends on how you want the math to work out in the long run.
The reason
you want to add the disks in large sets is so you have a more level writing of
the data to the disks - you don't want to get 3-4 'hot disks' slowing the whole
aggregate down until the data is spread evenly among the aggregate.'s new
disks...
-----Original Message-----
From:
owner-
Sent: Mon 3/19/2007 11:06
AM
To:
Cc:
Subject:
RE: FAS3020 - aggr best practises.
Point one reminds me of a question
I've been pondering. I've got a
filer using RAID-DP with 3X14-disk raid
groups, and currently 7 spares.
Ideally I'd only keep two spares, but I'm
still not clear on the
pros/cons of adding a 5 disk raid group, effectively
only adding three
more data disks to the volume.
I'm not in a
space crunch currently but I certainly will be at some
point. Is it
best to leave so many extra spares until I can add a full
raid group all at
once? Or in my case is it not that
important?
--
Michael W. Sphar - IS&T - Lead
Systems Administrator
SMBU Engineering Support Services, BMC
Software
________________________________
From:
owner-
On
Behalf Of Learmonth, Peter
Sent: Saturday, March 17, 2007 6:43 PM
To:
Darish Rajanayagam;
Subject: RE: FAS3020 - aggr
best practises.
Hi Darish
Welcome to NetApp and to
Toasters!
1. You can do an "aggr add aggr0 56" or use the
FilerView GUI and add
all 56 of the new disks into the existing
aggregate. You can physically
add the shelves and add them to the aggr
while the filer is up and
running. I see no disadvantages, and that is
the best practice. (Add
disks in large sets, ideally the raid group
size).