Thanks for all the responses. This is to meet an IOPS objective. I've run reallocate scans on the LUN's before, but it is not clear if that has done anything. Does a reallocate scan force the data to spread out on more spindles?
Suresh
-----Original Message----- From: Blake Golliher [mailto:thelastman@gmail.com] Sent: Monday, January 22, 2007 12:06 PM To: Suresh Rajagopalan Cc: Borders, Rich; toasters@mathworks.com Subject: Re: Aggregate expansion
That sounds fair. The thing you'll need to keep in mind is that all your data written to the 14 disks that you first created. After you add on the other set of disks, the data you write will likely be put there, since that's where the most free contiguous space is.
So if you are adding spindles for the space you need, and not to meet an IOP objective, you should be ok. If you are adding more disks, in an attempt to give more disk iop resources to the already existing data set, then it's a bit harder. If you have enough space, you can use reallocate to re spread out the data across the spindles.
Hope that helps, -Blake
On 1/22/07, Suresh Rajagopalan SRajagopalan@williamoneil.com wrote:
I mean with existing data on the aggregate.
To clarify, say I first create an aggregate with 14 disks (and default raid size). Then this aggregate is populated with data. After a period of time the aggregate is expanded by adding disks, say to 56 disks.
The question is, is there a difference (in performance, efficiency) between the aggregate as described above and an aggregate that was originally created from all 56 disks?
Suresh
-----Original Message----- From: Borders, Rich [mailto:Rich.Borders@netapp.com] Sent: Monday, January 22, 2007 11:25 AM To: Suresh Rajagopalan; toasters@mathworks.com Subject: RE: Aggregate expansion
Yes... You can make hot disks happen. Do you mean without adding any data?
Richard D Borders CPR Escalations Engineer RTP, North Carolina USA - Network Appliance, Inc. Email: rborders@netapp.com Phone:(919) 476-5236 Cell: (919) 606-5099 Fax: (919) 476-5608
-----Original Message----- From: Suresh Rajagopalan [mailto:SRajagopalan@williamoneil.com] Sent: Monday, January 22, 2007 12:46 PM To: toasters@mathworks.com Subject: Aggregate expansion
Is there any difference between creating an aggregate on a certain number of disks (say n) , and then later expanding the aggregate to
N
disks, as opposed to creating the initial aggregate on N disks?
Suresh