Inside Storage Networking

Cisco released a feature in NX-OS v8.3.1 called Automatic Zoning.  The feature does exactly what the name suggests:  it automatically configures zoning for the devices on your SAN.  You can see a video on the feature here: What Is Zoning? SAN (Storage Area Network) zoning is specifying which devices on the SAN  can communicate with which other devices.  Devices are added to a zone.  A zone is a group of devices that can communicate.  Zones are then added to a zoneset.  The zoneset is then activated - this is the configuration that is in effect. There can be multiple zonesets but only one active one at any given time.   By default, any device not zoned (not a member of a zone) cannot communicate with any other device.  A device that is in at least one zone is considered zoned.   Effective zoning prevents unauthorized devices from talking to each other, and minimizes disruptions on the SAN if a device misbehaves....

When I am working on performance problems, a frequent question I  get is why increasing buffer credits for a particular port is not a fix for a slow drain device attached to that port.  In this video, I explain the concept of congestion and illustrate why increasing the number of buffer credits is not a fix, without addressing the underlying cause of the congestion.   There are some exceptions to this rule.  The most common is when dealing with long-distance links, but that will be addressed in a future blog post (and perhaps a future video).   As always,  you can leave feedback in the comments, or find me on  LinkedIn  or  Twitter

Recently, there were enhancements made to several features, including a new Alert Policy feature in IBM Storage Insights Pro. You can find out what's new about the new features here.   The Alert Policy feature lets you configure a set of alerts into a policy and apply all of them across multiple storage systems. In this way you can ensure consistency with alerts and not have to define the same alert on each individual storage system. Once you define the alerts, IBM Storage Support representatives can see the generated alerts on a storage system. For the IBM FS9100, there are a number of alerts that are already defined. When one of those alerts is triggered,  a proactive ticket is opened and the experts at IBM Storage Support investigate the alert, then take whatever action is necessary.   With this post we'll take a look at how the IBM Storage Support Team investigates  alerts.  For this example we are using an alert for the Port Send Dela...

IBM Tech U Atlanta 2019 This is just a quick post to say that I will be at IBM Technical University in Atlanta. I will be there from April 29 through May 3 My sessions for this event are: s106417 The Path of an FC Frame Through a Cisco MDS Director s106420 Proactive Monitoring of a Cisco Fabric s106421 Troubleshooting Cisco SAN Performance Issues - Part 1 s106422  Troubleshooting Cisco SAN Performance Issues - Part 2 Find these sessions and many more at Technical University. Click the banner at the top of the page to register or for more information. As always, if you have any questions, leave them in the comments at the end of this blog or find me on LinkedIn or Twitter.

Why Low I/O Rates Can Result in High Response Times for Reads and Writes As IBM Storage Insights and Storage Insights Pro become more widely adopted, many companies who weren't doing performance monitoring previously are now able to see the performance of their managed storage systems. With the Alerting features on Storage Insights Pro, companies are much more aware of performance problems within their storage networks. One common question that comes up is why a volume with low I/O rates can have very high response times. Often these high response times are present even with no obvious performance impact at the application layer. These response time spikes generally measured in the 10s or 100s of milliseconds, but can be a second or greater. At the same time, the I/O rates are low - perhaps 10 I/Os per second or less. This can occur on either read or write I/Os. As an example, this picture shows a typical pattern of generally low I/O rates with a high response time. The volume...

IBM Storage Insights Pro Groups Feature In addition to the Reporting and Alerting features that are not available in the free version of IBM Storage Insights, the subscription based offering, IBM Storage Insights Pro, has a very useful feature called Groups. Groups allow you to group or bundle together related storage resources for ease of management. For example, you might group a set of volumes together that are all related to a specific application, or server cluster. You might group the hosts that make up a cluster into a group. You can even group ports together - you could define a group of ports for an SVC Cluster that includes all the ports used for inter-node communication.  Such a group would be very handy for your IBM Storage Support person. It would potentially save support from having to collect a support log and dig through it. It would certainly make analysis go faster when troubleshooting an issue. So to get started with Groups, the first thing to do is ...

Answers To Some Frequently Asked Questions about IBM Storage Insights Over the last several months I have seen some common questions that are asked about IBM Storage Insights. I started collecting them and will answer them here.  These questions are all about Storage Insights itself. Questions relating to managing specific types of storage with Storage Insights will be answered in future Blog posts. So, on to the questions..... Q: Can I install a data collector in the same system as my IBM Spectrum Control server A: Yes.  However you need to pay attention to memory and CPU usage of you Data Collector Authentication If you use usernname/password authentication configure a dedicated user ID for the Data Collector on  your  storage systems.  do not use the default or other Admin account.    This allows for effective auditing and reduces security risks.  Q: What Are The Recommended System Specifications for the Data Coll...