Re: Replicated File System Consistency
Date: Tue, 30 Dec 2008 09:55:47 -0800
> So we've got a half dozen or so Oracle 10G (10.2.0.3) servers with
> production data on them.
> Historically, we ran them with direct attached RAID arrays, but
> recently we moved them to a new data center with a netapp 3040 SAN.
> Performance on the new hardware seems about the same; SAN is
> theoretically faster but I think there's more latency so from what I
> can see its a wash.
> Question I have though is about dr and consistency.
> We have a second san offsite.
> I can configure san mirroring to mirror our primary san off to another
> data center (more accurately I can ask the san guys to do so).
> In the event of a catastrophy at my primary center, can I mount the
> mirror copy of the database in dr, go through a recovery, and be
> relatively comfortable I've got a conistent data set?
> I know that if I pull the plug on the machine, Oracle commits that,
> post recovery, I won't lose any commits and it'll be consistent
> (although the recovery may take a while).
> Does the same commitment hold if I'm using a lower level (block level)
> replication technology and the replication fails in some unexpected
> Sorry if this is an obscure question, but I don't understand the
> interaction of Oracle's file system with the SAN well enough to make
> intelligent recommendations to the DR guys.
David's link is a good one but I'd like to address the fact that you are not seeing any improvement from the NetApp 3040. Here are a couple of questions you might explore:
- What is the limiting factor? CPU? Network bandwidth/latency? Storage?
- How many LUNs? (one is never almost never the right answer)
- What RAID level?
- How is the cache configured? What percentage read? What percentage write?
- How many physical disks are you striped over for your hottest data files? -- Daniel A. Morgan Oracle Ace Director & Instructor University of Washington damorgan_at_x.washington.edu (replace x with u to respond) Puget Sound Oracle Users Group www.psoug.org