Category Archives: Data Storage

Vmware Datastore via NFS

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One of the objectives of our recently concluded massive storage upgrade project, was to replace our vmware datastore from iSCSI to NFS. I have been hearing the advantages of using NFS versus block-level storage (ie, iSCSI or Fiber Channel), and true enough NFS did not disappoint.

We have been using iSCSI on NetApp as datastore on vmware for a long time, and it has been running pretty well. But when we perform maintenance on the NetApp storage, the virtual machines were often times affected. In addition, restore procedures can be a pain.

While Fiber Channel (FC) is still the standard storage for most vmware implementation because of its proven technology, in my experience here are the advantages of using NFS over iSCSI or FC:

1. Robust, as long as you follow the best practices guidelines. For instance, separate the NFS network from the general use network. Vmware and NetApp released white papers discussing the NFS datastore best practices. In our environment, we did several failover on the NetApp storage to upgrade the Data ONTAP version, and the virtual machines were never affected.

2. Easier to configure both on the vmware side and the NetApp side.

3. Easier to backup, via NDMP on the NetApp side.

4. Easier to restore vmdk files using the snapshots on the NetApp side, since there is no need to mount LUNs.

5. Vmware and NetApp built great tools for seamless maintenance and operations.

NetApp Storage Migration Lessons

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One of my latest projects is to consolidate six old NetApp Filers and migrate a total of 30 TB of data to a new NetApp Filer cluster, FAS 3240C. The project started several months ago and it is almost complete. Only one out of six NetApp filers is left to migrate.

I have done several storage migrations in the past, and there are always new lessons to learn in terms of the technology, migration strategy and processes, and the people involved in the project. Here are some of the lessons that I learned:

  1. As expected, innovations in computer technology move too fast and storage technology is one of them. IT professionals need to keep pace or our skills become irrelevant. I learned storage virtualization, NetApp fast cache, and snapmirror using smtape, among many other new features.
  2. Migration strategy, planning, and preparation take more time than the actual migration itself. For instance, one filer only took an hour and a half to migrate. However, the preparations such as snapmirroring, re-creating NFS and CIFS shares, making changes in users login scripts, making changes in several applications, and many other pre-work were done several days before the actual migration. The actual migration is actually just to catch up with the latest changes in the files (ie snapmirror update), and flipping the switch.
  3. People, like many other big IT projects, are always the challenging part. The key is to engage the stakeholders (business users, application owners, technical folks) early on in the project. Communicate with them the changes that are happening and how their applications and accesses to their data will be affected. Give them time to understand and make changes to their applications. Tell them the benefits of the new technology and communicate often the status of the project.