ORIGINALLY PUBLISHED 27th May 2015 Thin provisioning is a well understood technology in the storage industry, but a surprising number of you haven’t actually deployed it yet due to the “what-ifs” that keep you up at night.  In this post I will hopefully give you a pointer to my thoughts about how you could address some of these concerns.   Those of you who have already deployed Thin Provisioning will hopefully also find something interesting hiding in here. Almost all of this will apply to the using real time compression as an alternative to Thin Provisioning. What do you mean by… [Read More]

ORIGINALLY PUBLISHED 10th February 2016 Hi All, I got this question from a customer and thought it was worth a discussion. The short answer is yes you can perform both compression and encryption on data – as long as you do the steps in the correct order. The problem is that encrypted data is basically uncompressable, so you have to make sure you perform the steps in the correct order. Compress then encrypt – this works fine Encrypt then compress – this basically results in no compression savings at all  Inside both the SVC and the Storwize, we make sure… [Read More]

ORIGINALLY PUBLISHED 17th March 2016 Hi, There have been a number of DRAID questions on the forums recently, so we thought it was worth giving you some extra details about the benefits of DRAID. Ian Boden has provided the following information, and if you ask nicely he may come back and give us some more details in the future. Please feel free to ask additional questions in the comments and we will do our best to answer them. You may also be interested in this question in the forum about multiple drive failures: https://www.ibm.com/developerworks/community/forums/html/topic?id=907358ae-9320-43cf-9a12-709f2555872d Hope this is helpful Andrew Hello… [Read More]

ORIGINALLY PUBLISHED 13th June 2016 Hi All, I was at the US user group last week – and this topic came up quite a lot.  The main reason that we started discussing R5 versus R6 is because the development team are currently recommending that all Distributed RAID arrays be configured as R6, and people are remembering the whole “R6 is slower than R5” adage that has been around for some time.  So let’s consider the pros and cons: Reads Lets start with Reads – because that is simpler.  When a RAID array is fully redundant (no drives offline or rebuilding)… [Read More]

ORIGINALLY PUBLISHED 15th June 2016 Hi All, I’ve been working with a customer and we’ve realised that our best practice for snapshots (or Thin provisioned FlashCopies with a background copy rate of zero) may have been slightly flawed.   There is no functional impact to these changes- but we can make some small changes that will have a beneficial impact on performance.  There are actually 2 recommendations here: The first one is trivial to fix and can have a measurable impact. This applies to all forms of thin provisioned and compressed volumes, but they are most likely to be interesting if… [Read More]

ORIGINALLY PUBLISHED 11th November 2017 Hi everyone, I have been asked to write up some hints and tips about how to do scripting on SVC / Storwize / Spectrum Virtualize.  I do a lot of scripting against our products – sometimes scripts that get published on developerworks (e.g. the Standby Node Script) and sometimes smaller scripts to help clients with specific issues. There are a few basic things that we need to understand when doing scripting.  Hopefully the tips below make some sense to you and will prove helpful. Finding the commands that you need to run How to do… [Read More]

ORIGINALLY PUBLISHED 31 May 2017 Hi again, With the User Group and IBM TechU this month I have a load of Blog posts that I’ve said I’ll write – so you might see them coming a bit fast this month. There is a new EasyTier feature that we released in 780 called “Warm Promote”.   This is aiming to address a potential issue when you have a Nearline tier.   I want to stress that I can’t think of a single case where the problem I’m going to describe below caused a major issue for a client – but it’s a good… [Read More]

ORIGINALLY PUBLISHED 14th October 2015 The support team are telling me that a lot of people are surprised by a new feature we introduced in SVC 7.5, which we didn’t do the best job in describing or documenting.  What you are seeing is a new Running Task appearing in the GUI when you create a new fully allocated volume that says “Volume Format” – a lot like this: In the Volumes view – the volume is also shown as “Online (formatting) “ So what’s going on? Let me tell you. The problem we are solving is that when you are… [Read More]