• Linked Applications
    Loading…

The Rebalance script for IBM SVC has been updated

I found this in the Aussie Storage Blog

http://aussiestorageblog.wordpress.com/2013/04/22/ibm-scripting-tools-for-svc-and-storwize-has-been-updated/

 

Rebalancing of managed disk groups has to be done whenever you add new mdisks to a group - otherwise the IOPS and response
times on these managed disk groups become unbalanced and you will not see the expected performance out of the group.

Icon

SVC / Storwize Version 7.3 can automatically rebalance the workloads across the mdisks. If you have switched this on, this rebalance script should no longer be used.

It seems that the algorithm is checking the workload an all mdisks to build a candidate lists of Volumes to be redistributed. To become a rebalance candidate a disk must have a statistically high load.

We have seen the following. Disks which have high load for small time periods will probably never become a candidate for redistribution because their average usage is low. We have seen these disks struggling with performance because they have only be striped across some mdisks. We also have seen that the other volumes of this mdisk group run into problem because they stripe also across the mdisks with the high load. These unbalanced volumes have to be identified with an appropriate analysis and redistributed manually. 

We can help you with an analysis

More informations about unbalanced mdisk groups here

BVQ howto - Analyze MDisk Groups.pdf

 

Click on pictures to enlarge


in this picture you can see that most of the IO is handeled by only one managed disk.
It handles three times more IO than the other mdisks. This mdg will become a
performance problem soon when this one mdisk becomes more load and saturates.

 

This is how it is lookiong like in performance view. The green lines are IOPS from the
one mdisk and another with smaller load and thge red lines are the response times.
It is obvious that response time of the high load mdisk will become an issue soon.

 

 

 


Popular content:

Page: Performance bottleneck analysis on IBM SVC and IBM Storwize V7000 , Page: Downloads and BVQ releases , Page: BVQ installation manual , Page: BVQ use cases and experiences , Page: Solved buffer credit wait situation at a customer side


General links

Return on invest 

Performance analysis whitepapers


The BVQ Blog
SVC / Storwize monitoring, reporting and performance analysis solution. BVQ is the fastest and complete performance analysis tool for IBM storage virtualization.
New BVQ offline scanner now scans Storwize drive performance information
We just released the new offline scanner which will now also scan the drive information from any Storwize product. Direct Link to BVQ offline scanner http://bvqwiki.sva.de/x/3IBdAQ With this we can make more accurate statements about the...
BVQ V3.3.3 with great improvments for performance analysis released
We just released the new BVQ V3.3.3 with great enhancements in performance and usage of the performance analysis methods. We are in progress to translate the release notes to English. If you want to download V3.3.3 now you can do this from the German...
Thoughts about storage monitoring or monitoring or analysis?
  I had a discussion about storage monitoring and analysis. This discussion ended in the following understanding: Monitoring with a simple product help you to understand when things go wrong. They show the symptoms but not the...
Sneak preview BVQ dashboard will greatly enhance storage monitoring capabilities
The BVQ development team is currently working on the new BVQ dashboard functionality. This new dashboard should become available in 1H2015. The dashboard is great for monitoring, you can open several dashboards and put them onto different screens, this...
BVQ is so incredibly fast! Leads to SVC / Storwize performance analysis results in seconds instead of minutes or hours
This is just a new experience with the newest BVQ Beta code which will become available as BVQ Version 3.4 in some weeks. BVQ Version 3.4 will have a completely refurnished internal data handling which you will not recognize as a benefit today but this...
Analysis of SVC remote copy performance problem
This is an example of an successful latency peak analysis were we found the reason of a performance problem in the remote copy connection.  It is very complex to analyze RC performance problems but the BVQ Copy Services Package adds all tools needed to...
New SVC / Storwize /Flash and BVQ customer reference Bitmarck
  Find more details in the BVQ reference pages in English in German   TASK Expansion and optimization of SAN infrastructure for a higher performance and an...
Success Story: Upper cache congestion problems led to a performance collapse – solved in hours!
In short Special circumstances can cause an overload of the SVC/Storwize upper cache. The impact of this situation can be very dramatic.  In this example, the customer environment was near to a complete standstill. It is sometimes amazing how quickly...
BVQ V3.3.2 with SVC/ Storwize V7.4 support available for download
BVQV3.3.2 has toleration support for V7.4 which means that everything is supported without the new V7.4 features encryption and child pools. These will be supported with the upcoming BVQ V3.4   Download here http://bvqwiki.sva.de/x/x4Ft...
The BVQ story ... storage cost reduction, bottleneck analysis and added business value for SVC and Storwize
The BVQ story ... The storage challenge Even a small storage environment may be complex. Questions about cost optimization or availability are hard to answer because the knowledge about actual and future...

(.)