Archives for November 2013


Singe File Restore – Fairy Tale Ending Going Down History Lane

If I go back to my earliest sysadmin days where I had to restore a file from a network share, I was happy just to get the file back. Where I worked we only had tape and it was crapshoot at the best of times. Luckily, 2007 brought me a SAN to play with.

bad times with dealing with LUNSThe SAN made it easier for sure to go back into time and find that file and pull it back from the clutches of death by using hardware based snapshots. It was no big deal to mount the snapshot to the guest but fighting with the MS iSCSI initiator got pretty painful, partly because I had a complex password for the CHAP authentication, and partly because clean-up and logging out of the iSCSI was problematic. I always had ton of errors, both in the windows guest and in the SAN console which caused more grief than good it seemed.

Shortly after the SAN showed up, VMware entered my world. It was great that I didn’t have to mess with MS iSCSI initiators any more but it really just moved my problem to the ESXi host. Now that VMware had the LUN with all my VMs, I had to worry about resignatureing the LUN so it wouldn’t have conflicts with the rest of production VMs. This whole process was short lived because we couldn’t afford all the space the snapshots were taking up. Since we had to use LUNS we had to take snapshots of all the VMs even though there were a handful that really need the extra protection. Before virtualization we were already reserving over 50% of the total LUN space because snapshots were backed by large block sizes and ate through space. Due to the fact that we had to snapshot all of the VMs on the LUN we had to change the snap reserve to 100%. We quickly ran out of space and turned off snapshots for our virtual environment.

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NOS 3.5.1: PAM Cards For The Cost of Stick of RAM

General Availability of the NOS 3.5.1 went live today. Lots of great features but my favorite is having the power of software and a stick of RAM to give a PAM card in your back pocket to be used at will. We always had the option but you had to mess around with advanced settings. Today as you add more RAM to a our virtualized storage controller, the extent(read) cache will grow automatically. Keep it mind this cache lives directly beside the virtual workloads and not across the network. Write performance also received a boost with code release as well.

NOS 3.5 includes the following new features.

• HTML5 administration interface that replaces the previous Flex interface
• Active Directory/LDAP authentication
• Public REST API
• User-manageable SSH keys and Controller VM lock down
• SNMPv3 support and Nutanix MIB
• Deduplication of guest VM data on the premium tiers (RAM/Flash)
• Optimization of linked clones aka Shadow Clones
• Container and vDisk space reservations
• Compression of remote replication network traffic
• Storage Replication Adapter (SRA) for VMware Site Recovery Manager
• General availability of KVM
• Technology preview of Hyper-V
• Automated metadata self healing
• Auto-Teiring between high performance and capacity drives is working in 4 MB chunks, if its flash, the data is HOT.


Grey Cup Kickoff with WBM and Nutanix

This is event is deep in Riderville aka Regina, your interested email ktischler AT wbm DOT ca. It going to be fun, informative and sports related.

Grey Cup Kickoff - Nutanix

Grey Cup Kickoff – Nutanix


Big or Small, Scale Matters in Operations

Sometimes scale get contrived as huge or some quantity of capacity in IT that few shops will ever get to. I think big or small all companies need to the ability to scale. The ability to scale allows customers to buy want they need, when they need it and most importantly use it right away. It can be 6 TB or 60 PB, it’s all relative.

The prized gem for Nutanix and it’s ability to scale revolves around Apache Cassandra(NoSQL) and paxos. Nutanix stores it’s metadata in Apache Cassandra There is a good write up on how Paxos works with NoSQL on Nutanix on the Nutanix Bible. I really enjoyed the ending of a recent article, “Next gen NoSQL: The demise of eventual consistency?”

The next generation of commercial distributed databases with strong consistency won’t be as easy to build, but they will be much more powerful than their predecessors. Like the first generation, they will have true shared-nothing distributed architectures, fault tolerance and scalability.

Why did I enjoy it? Because this is what Apache Cassandra (NoSQL) and paxos is giving to Nutanix today. NoSQL is powerful tool for responding to change and combined with paxos all worries go away. NoSQL’s ability not to need a strict schema allows Nutanix respond to change very efficiently in terms of:

Failures – Nutanix Cassandra has self ring healing in 3.5 where the metadata is evenly distributed. If cassandra process on a node is down for more than 5 minutes. Medusa will trigger the process of detaching the node from cassandra ring. Once the node is detached from the ring, we are ready to take another failure and still remain available.

Upgrades – Only that is constant is change! Nutanix is rapidly adding features and our customers can’t afford downtime. I just read a couple of days ago of company adding dedupe to their product line and the upgrade needed planned downtime. NoSQL allowed Nutanix to add SHA1 hashes to the metadata and carry on to provide inline dedupe without downtime.

Scaling – Nutanix can scale compute and storage at different rates with a variety of different nodes. The process is the same for all the nodes. Hit the expand cluster button, enter in three IP’s, add to the compute node to vCenter. You also have the ability to automate the whole thing! Keep in mind this process is the same for ESXi, Hyper-V and KVM.
Expand Cluster
Scaling is the ability to respond to business change.