Category Archives: Storage

VMware Path Masking

  I’ve written posts in the past regarding LUN masking on a storage array, but it is possible to mask a path directly from your vSphere environment.  I feel that if at all possible the masking should be handled at array level because the array is closest to the disk.  Let’s face it, if vSphere… Continue Reading

Network RAID Penalty

I recently got my hands on a pair of HP P4300s in the lab and wanted to see how the performance was with Network RAID.  One of the most read posts on this site is on Understanding RAID Penalty and I was curious to see how Network RAID played into this equation. Basic Setup I… Continue Reading

Netapp AggrSpaceCheck 2.0 needed

I was recently helping out a company attempt to upgrade their Netapp Filer from OnTap 7.3 over to Data OnTap 8.  We ran the Netapp Upgrade advisor and got to a section that wanted us to run the AggrSpaceCheck tool to make sure that the aggregates had sufficient space available.  Normally, I skip this step… Continue Reading

Netapp VASA Provider 1.0

Netapp has released their vStorage APIs for Storage Awareness (VASA) provider 1.0 to their support site. If you’re not that familiar with the VASA concept, this article should explain what it is and how it’s used in regards to VMware vSphere 5. What is VASA? VASA Providers collect information about your storage systems and present… Continue Reading

SQL HA Mirroring with vCenter

We’re probably all aware of the benefits of clustering things like SQL Server in order to provide highly available data.  But shared storage clustering has some drawbacks on VMware ESXi clusters such as not being able to vMotion. • Database Mirroring – SQL Server database mirrors utilize a non-shared storage availability solution, using built-in SQL… Continue Reading

Understanding RAID Penalty

Determining which type of RAID to use when building a storage solution will largely depend on two things; capacity and performance. Performance is the topic of this post. We measure disk performance in IOPS or Input/Output per second. One read request or one write request = 1 IO.  Each disk in you storage system can… Continue Reading

Lun Masking vs Zoning

Zoning and Lun Masking are often confused for each other, probably because both of them are used to restrict access to storage.  They should both be used to secure the storage network and reduce unnecessary traffic. Zoning If you want to specify only certain hosts from accessing a storage device then you would want to… Continue Reading

Path Selection Policy with ALUA

It’s important to understand how VMware ESXi servers handle connections to their associated storage arrays. If we look specifically with fibre channel fabrics, we have several multipathing options to be considered. There are three path selection policy (PSP) plugins that VMware uses natively to determine the I/O channel that data will travel over to the… Continue Reading