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Tag Archives: performance

Performance Part V

Here’s the last of the performance measurements for now. Logical Disk Performance – monitoring of LDEVs. There are three main groups Tuning Manager can monitor; IOPS, throughput (transfer) and response time. The first two are specific to particular environments and the levels for those should be set to local array performance based on historical measurement over a couple of weeks. ... Read More »

Performance Part III

Next under discussion for performance is array groups. First the background (and as usual, apologies to those who already know all this). HDS enterprise arrays lay their disks out in array groups, either RAID-1/0, RAID-5 and RAID-6. Variable size LUNs are then carved out of the array groups for presentation to hosts. Obviously it makes sense to ensure that every ... Read More »

Using Tuning Manager for something useful – Part I

Stephen commented about Tuning Manager and doing something useful with the data. I thought I would use this as an opportunity to highlight some of the things I look at on a regular basis (almost daily, including today in fact). Part I – Write Pending. First a little bit of background; Write Pending is a measure of unwritten write I/Os ... Read More »

Tuning Manager CLI

I’ve been working with the HiCommand Tuning Manager CLI over the last few days in order to get more performance information on 9900 arrays. Tuning Manager (5.1 in my case) just doesn’t let me present data in a format I find useful, and I suppose that’s not really surprising as, unless you’re going to add a complete reporting engine into ... Read More »

Developing a Tiering Strategy

Implementing a storage tiering strategy is a big thing these days. Everyone should do it. If you don’t then you’re not a “proper” storage administrator. Being serious and moving away from the hype for a second, there is a lot of sense in implementing tiering. It comes down to 1 thing – cost. If disk and tape storage was free, ... Read More »

Standards for Measuring Performance

I had a bit of banter following a post I made on ITToolbox earlier in the week. The question was posed as to why major disk array vendors (other than Netapp) don’t produce performance statistics. There are benchmarks; the Standard Performance Evaluation Corporation and Storage Performance Council for instance. However SPEC only covers NAS and neither HDS and EMC sign ... Read More »