Here's a good document to browse over for this particular issue...
http://www.netapp.com/library/tr/3437.pdf
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From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Jason Herring Sent: Monday, March 19, 2007 3:08 PM To: Sphar, Mike; toasters@mathworks.com 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-toasters@mathworks.com on behalf of Sphar, Mike Sent: Mon 3/19/2007 11:06 AM To: toasters@mathworks.com 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?
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Michael W. Sphar - IS&T - Lead Systems Administrator
SMBU Engineering Support Services, BMC Software
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From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Learmonth, Peter Sent: Saturday, March 17, 2007 6:43 PM To: Darish Rajanayagam; toasters@mathworks.com 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).