Moving from 14->56, no.
WAFL does not immediately go and lay out the original data again across all disks. As such, initially new writes should get spread across all of these disks. Thus, one might see a read difference in the near-term that would smooth out over time (IOW, reads from the 'old' 14 disks can only come from those 14 disks.. whereas new reads can come from all 56 disks).
(To Rich's point, if you say, went from 56 to 60 disks, the possibility for new writes to go to just the 4 disks for a period of time exists as WAFL "levels" itself out over time.. that would be "hot" disks.)
Hope this helps.
-jbl
-----Original Message----- From: Suresh Rajagopalan [mailto:SRajagopalan@williamoneil.com] Sent: Monday, January 22, 2007 2:29 PM To: Borders, Rich; toasters@mathworks.com Subject: RE: Aggregate expansion
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