I'd second Stefan's comment. User error is generally the cause of downtime, not hardware outages (assuming a reasonably architected sytem from a redundancy standpoint). Complicating things generally makes you more prone to outages, not less.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Stefan Funke Sent: Friday, April 08, 2011 2:18 AM To: toasters@mathworks.com Subject: Re: Distribute aggregate across shelves or limit to one shelf?
Whatever you do, there is always a tradeoff between reliability, performance and efficiency. I think all concerns are well answered in NetApps storage resiliency paper: Do Raid-DP, do backups, do HA, do multi-pathing, do disk auto assign, have spare parts (etc) and you'll have 99,999% availability and a max of performance, as long as you can afford it.
And btw., limiting you and your system to have 1 aggregate/shelf produces a lot of work reassigning disks/spares over time when your systems grows. After 10+ years of operating netapp systems, I always had my aggregates (volumes earlier) spread across all shelves and never had any trouble with it.
-SF
Am 07.04.2011 21:58, schrieb Ray Van Dolson:
Best practice (based on my reading of the archives) seems to be to distribute disk membership in an aggregate across disk shelves.
This would appear to be for performance reasons primarily (less chance
of saturating a shelf's "uplink" to the controller), but how does it affect reliability?
If I limit myself to one aggregate per shelf, if I lose that shelf I lose only the one aggregate. If aggregates are distributed I could lose all of them.
My thought is that the chance of the shelf failing is actually pretty slim as its hardware isn't all that sophisticated.
And obviously there are performance penalties for limiting to one aggregate per shelf (disk count maximums).
Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.