A NetApp Technical Diary

What’s an IOP, and why do I care?

gary — Tue, 21 May 2013 12:09:33 +0000

Recently I was talking to a network guy about storage IOPS, when he asked me. What is an IOP exactly? Immediately I remembered having the exact same question when I first started seriously working with storage gear back in 2006. I knew that an IOP was an I/O Operation, and IOPS is typically meant to [...]

VMware performance for guru’s.

gary — Fri, 03 May 2013 12:24:54 +0000

I am definitely not a guru yet. But one day…. VMware Performance for Gurus – A Tutorial from Richard McDougall

Predicting disk cache hits for 100% random access.

gary — Tue, 23 Apr 2013 10:20:47 +0000

Lets say I have a cache of 512G. My block size is 4K, so that’s 134,217,728 entries. How many blocks will I need to read to fill the cache? Well if I read data sequentially, then obviously I just need to read 512G worth of files. But what if I read random blocks? Most caches [...]

Show status of aggregate creation / disk zero status.

gary — Mon, 14 Jan 2013 19:16:47 +0000

For the most part, you only really care about disk zeroing if you’re waiting for an aggregate to be created on disks that were previously used on an old aggregate that was only just destroyed. To see how long disk-zeroing is taking, use the command “aggr status -r” filer-6280*> aggr status -r Aggregate aggr1_large (creating, [...]

Netapp API hacking with python

gary — Wed, 09 Jan 2013 19:14:20 +0000

As a non-programmer, I’ve always been reticent to use anything with acronyms like API and SDK, relying instead on issuing a full command line using rsh or ssh. That works for a while until you want to start doing things like checking for errors – and until you get fed up with 90% of the [...]

Thoughts on “Latency Numbers Every Programmer Should Know”

gary — Wed, 02 Jan 2013 23:35:13 +0000

Last week a number of twitter users were posting about a very cool looking interactive latency predicterizor. In the small world of computer performance nerds, it was a veritable tsunami of attention. My twitter skills are so feeble that I cannot figure out how to determine the total number of tweets – but as of [...]

Thinking Clearly about Performance – ACM Queue article.

gary — Thu, 20 Dec 2012 02:38:17 +0000

Great article from Cary Millsap, covers performance analysis in general – not specific to Oracle. Thinking Clearly about Performance – ACM Queue

Oracle performance diagnostics (Session centric)

gary — Wed, 19 Dec 2012 14:11:42 +0000

Anyone who deals with systems performance in an enterprise environment, will inevitably need to deal with an Oracle database performance problem. These databases often make up parf of the largest, most complex and business critical infrastructures. In the past I have always looked at DB performance issues from a systemic perspective – looking at the [...]

Retiring from NetApp technical blogging

Chris Kranz — Wed, 12 Dec 2012 10:19:37 +0000

Those that view this site regularly, I apologise for the lack of updates. About 2 years ago I significantly moved roles, I moved into much more of an architects role and started engaging at a higher level with my customers. This means I’m really not as hands on with NetApp technology as I used to be. I’ve noticed this more as I’ve been designing new NetApp technology and I have to lean on our skilled consultants more to help with the technical detail. I really hope that the information on this website still serves as a great reference for people and that it continues to have great success, but I’m afraid I won’t be able to commit any new content here.

As my role has changed, I’ve decided to re-invent my online presence, so this isn’t the end of my social networking involvement! You can still find me on Twitter @ckranz and I have started a new blog with more relevance to what I’m doing now. As I am now a Solutions Architect, involved in cloud designs, high level strategies and general thoughts, it seems fair that I continue share my experiences.

Please visit my new blog at: outofthis.net/work for continued stories and thoughts from me. I certainly haven’t hung up my NetApp hat just yet, but I don’t feel I can help the community with my technical expertise and knowledge any more.

If you are interested in being a guest blogger on WAFL to share your NetApp skills and experiences, please get in contact. This has become a popular website and it’d be great to see fresh new content on it again.

Effects of Windows power management on storage performance.

gary — Wed, 14 Nov 2012 21:14:29 +0000

Something very odd happened on my Jetstress box. I disconnected my iSCSI LUN’s in order to do an aggregate snap-restore, and when I restarted the test – the oprate achieved from Jetstress (with the exact same parameters) was around 1/2 of what it had achieved just a few minutes ago. It looks like power-savings kicked [...]