ZFS Replication and Recovery with FreeNAS

We get requests to recover data from a secondary platform all the time. RPO (recovery point objective) of 30 minutes can be challenging to small to medium sized companies, especially if there is an SLA (service level agreement) to meet.

This week, my team and I took some time to create a FreeNAS replication demo for a potential client. I thought I document the whole thing about ZFS replication, the key steps to set it up and show how recovery is done.

ZFS Snapshots

ZFS replication relies on periodic ZFS snapshots. ZFS snapshot is an inherent feature from the ZFS file system, and often used as a point-in-time copy of the existing ZFS file system tree in memory. Once a snapshot has been triggered, either manually or on schedule (periodic), the file system tree and its metadata in the memory are committed to disk to ensure an updated and consistent state of the file system at all times.

To start, a running snapshot policy on a schedule must be in place. This snapshot policy can be on a specific dataset or zvol, or even the entire zpool. Yeah, I am using quite a few ZFS terminology here – zpool, zvol, dataset. You can read more about each of the structures and more here.

Once the ZFS replication task has been setup, every snapshot occurred in the snapshot policy is automatically duplicated and copied to the target ZFS dataset. Usually, the target ZFS dataset is on a secondary FreeNAS storage server, serving as a disaster recovery platform. Sending and receiving data in the snapshots rely on SSH service.

This is the network diagram explaining the FreeNAS ZFS replication setup.

Continue reading

Brainy Commvault

[Disclosure: I was invited by Commvault as a Media person and Social Ambassador to their Commvault GO 2019 Conference and also a Tech Field Day eXtra delegate from Oct 13-17, 2019 in the Denver CO, USA. My expenses, travel, accommodation and conference fees were covered by Commvault, the organizer and I was not obligated to blog or promote their technologies presented at this event. The content of this blog is of my own opinions and views]

The waltz across the Commvault-Hedvig mine field will not be easy. Commvault will have a lot of open discussions about their acquisition of Hedvig and how Hedvig “primary storage platform” will fit into a “secondary storage framework” of Commvault. The outcome of this consummation is yet to appear as a structured form. The storyline will eventually form as Commvault’s diligence to define their strategy moving forward.

Day 1

Day 1 was my open day at Commvault GO. I was absorbing the first impressions of Commvault again even though this was my third Commvault GO, after Washington DC and Nashville in 2017 and 2018 respectively. There was certainly a “startup” feeling again in Commvault since the appointment of Sanjay Mirchandani as CEO 9 months ago.

A lot of excitement and buzz were generated around the metallic, the Commvault venture into Software-as-a-Service (SaaS). The SaaS solution is targeted at the mid-market for organizations with 500-2500 staff count. Its simplicity and pricing were the 2 things which gave me a good feeling all over. There is even a 45-day trial for metallic.

Getting Brainy

My Day 2 itinerary was more specific because my agenda for this trip was to seek answers to the realization of Commvault-Hedvig.

Commvault took the distinction of using the vision of a DataBrain (#databrain) to define their strategy. From the picture below, the left and right hemisphere of the DataBrain forms the Storage Management piece on the left and Data Management on the right.

Continue reading

Commvault coming all together

[Disclosure: I was invited by Commvault as a Media person and Social Ambassador to their Commvault GO 2019 Conference and also a Tech Field Day eXtra delegate from Oct 13-17, 2019 in the Denver CO, USA. My expenses, travel, accommodation and conference fees were covered by Commvault, the organizer and I was not obligated to blog or promote their technologies presented at this event. The content of this blog is of my own opinions and views]

This trip to the Commvault GO conference was pretty much a mission to find answers to their Hedvig acquisition just a month ago. It was an unprecedented move for Commvault and I, as an industry observer and pundit, took the news positively. I wrote in my blog about Commvault’s big bet and I liked their boldness in their approach.

But the news did not bode well back here in Malaysia. The local technology news portal, Data Storage Asean picked up the news in a rather unconvinced way. 2 long time Commvault partners I spoke to were obviously unhappy because the acquisition made little sense to them on the back of closing of the Commvault Malaysia office just weeks before this with more unsettling rumours of the Commvault team in Asia Pacific. The broken trust and the fear of what the future held for the Commvault customers in Malaysia and in the region were riding along with me on this trip.

But I have seen the beginning of the Commvault transformation from the Commvault GO conferences I have attended since 2017. This is my 3rd Commvault GO and I ended Day 1 with good vibes.

Here were some of my highlights in the first day. Continue reading

Commvault big bet

I woke up at 2.59am in the morning of Sept 5th morning, a bit discombobulated and quickly jumped into the Commvault call. The damn alarm rang and I slept through it, but I got up just in time for the 3am call.

As I was going through the motion of getting onto UberConference, organized by GestaltIT, I was already sensing something big. In the call, Commvault was acquiring Hedvig and it hit me. My drowsy self centered to the big news. And I saw a few guys from Veritas and Cohesity on my social media group making gestures about the acquisition.

I spent the rest of the week thinking about the acquisition. What is good? What is bad? How is Commvault going to move forward? This is at pressing against the stark background from the rumour mill here in South Asia, just a week before this acquisition news, where I heard that the entire Commvault teams in Malaysia and Asia Pacific were released. I couldn’t confirm the news in Asia Pacific, but the source of the news coming from Malaysia was strong and a reliable one.

What is good?

It is a big win for Hedvig. Nestled among several scale-out primary storage vendors and little competitive differentiation, this Commvault acquisition is Hedvig’s pay day.

Continue reading

The waning light of OpenStack Swift

I was at the 9th Openstack Malaysia anniversary this morning, celebrating the inception of the OpenInfra brand. The OpenInfra branding, announced almost a year ago, represented a change of the maturing phase of the OpenStack project but many have been questioning its growing irrelevance. The foundational infrastructure components – Compute (Nova), Image (Glance), Object Storage (Swift) – are being shelved further into the back closet as the landscape evolved in recent years.

The writing is on the wall

Through the storage lens, I already griped about the conundrum of OpenStack storage in Malaysia in last year’s 8th anniversary. And at the thick of this conundrum is OpenStack Swift. The granddaddy of OpenStack storage has not gotten much attention from technology vendors and service providers alike. For one, storage vendors have their own object storage offering, and has little incentive to place OpenStack Swift into their technology development. Continue reading

Storage Performance Considerations for AI Data Paths

The hype of Deep Learning (DL), Machine Learning (ML) and Artificial Intelligence (AI) has reached an unprecedented frenzy. Every infrastructure vendor from servers, to networking, to storage has a word to say or play about DL/ML/AI. This prompted me to explore this hyped ecosystem from a storage perspective, notably from a storage performance requirement point-of-view.

One question on my mind

There are plenty of questions on my mind. One stood out and that is related to storage performance requirements.

Reading and learning from one storage technology vendor to another, the context of everyone’s play against their competitors seems to be  “They are archaic, they are legacy. Our architecture is built from ground up, modern, NVMe-enabled“. And there are more juxtaposing, but you get the picture – “We are better, no doubt“.

Are the data patterns and behaviours of AI different? How do they affect the storage design as the data moves through the workflow, the data paths and the lifecycle of the AI ecosystem?

Continue reading

Whither HPC, HPE?

HPE is acquiring Cray Inc. Almost 3 years ago, HPE acquired SGI. Back in 2017, HPE partnered WekaIO, and invested big in the latest Series C funding of WekaIO just weeks ago.

Cray, SGI and WekaIO are all strong HPC technology companies. Given the strong uptick in the HPC market, especially commercial HPC, we cannot deny HPE’s ambition to become the top SuperComputing and HPC vendor in the industry. Continue reading

Did Cloud Kill LTFS?

I like LTFS (Linear Tape File System). I was hoping it would take off but it has not. And looking at its future, its significance is becoming less and less relevant. I look if Cloud has been a factor in the possible demise of LTFS in the next few years.

What is LTFS?

In a nutshell, Linear Tape File System makes LTO tapes look like a disk with a file system. It takes a tape and divides it into 2 partitions:

  • Index Partition (XML Index Schema with file names, metadata and attributes details)
  • Data Partition (where the data resides)

Diagram from https://www.snia.org/sites/default/orig/SDC2011/presentations/tuesday/DavidPease_LinearTape_File_System.pdf

It has a File System module which is implemented in supported OS of Unix/Linux, MacOS and Windows. And the mounted file system “tape partition” shows up as a drive or device.

Assassination attempts

There were many attempts to kill off tapes and so far, none has been successful.

Among the “tape-killer” technologies, I think the most prominent one is the VTL (Virtual Tape Library). There were many VTLs I encountered during my days in mid-2000s. NetApp had Alacritus and EMC had Clariion Disk Libraries. There were also IBM ProtecTIER, FalconStor VTL (which is still selling today) among others and Sepaton (read in reverse is “No Tapes’). Sepaton was acquired by Hitachi Data Systems several years back. Continue reading

Figuring out storage for Kubernetes and containers

Oops! I forgot about you!

To me, containers and container orchestration (CO) engines such as Kubernetes, Mesos, Docker Swarm are fantastic. They scale effortlessly and are truly designed for cloud native applications (CNA).

But one thing irks me. Storage management for containers and COs. It was as if when they designed and constructed containers and the containers orchestration (CO) engines, they forgot about the considerations of storage and storage management. At least the persistent part of storage.

Over a year ago, I was in two minds about persistent storage, especially when it comes to the transient nature of microservices which was so prevalent and were inundating the cloud native applications landscape. I was searching for answers in my blog. The decentralization of microservices in containers means mass deployment at the edge, but to have the pre-processed and post-processed data stick to the persistent storage at the edge device is a challenge. The operative word here is “STICK”.

Two different worlds

Containers were initially designed and built for lightweight applications such as microservices. The runtime, libraries, configuration files and dependencies are all in one package. They were meant to do simple tasks quickly and scales to thousands easily. They could be brought up and brought down in little time and did not have to bother about the persistent data stored by the host. The state of the containers were also not important to the application tasks at hand.

Today containers like Docker have matured to run enterprise applications and the state of the container is important. The applications must know the state and the health of the container. The container could be in online mode, online but not accepting data mode, suspended mode, paused mode, interrupted mode, quiesced mode or halted mode. Each mode or state of the container is important to the running applications and the container can easily brought up or down in an instance of a command. The stateful nature of the containers and applications is critical for the business. The same situation applies to container orchestration engines such as Kubernetes.

Container and Kubernetes Storage

Docker provides 3 methods to local storage. In the diagram below, it describes:

Continue reading

WekaIO controls their performance destiny

[Preamble: I have been invited by GestaltIT as a delegate to their Tech Field Day for Storage Field Day 18 from Feb 27-Mar 1, 2019 in the Silicon Valley USA. My expenses, travel and accommodation were covered by GestaltIT, the organizer and I was not obligated to blog or promote their technologies presented at this event. The content of this blog is of my own opinions and views]

I was first introduced to WekaIO back in Storage Field Day 15. I did not blog about them back then, but I have followed their progress quite attentively throughout 2018. 2 Storage Field Days and a year later, they were back for Storage Field Day 18 with a new CTO, Andy Watson, and several performance benchmark records.

Blowout year

2018 was a blowout year for WekaIO. They have experienced over 400% growth, placed #1 in the Virtual Institute IO-500 10-node performance challenge, and also became #1 in the SPEC SFS 2014 performance and latency benchmark. (Note: This record was broken by NetApp a few days later but at a higher cost per client)

The Virtual Institute for I/O IO-500 10-node performance challenge was particularly interesting, because it pitted WekaIO against Oak Ridge National Lab (ORNL) Summit supercomputer, and WekaIO won. Details of the challenge were listed in Blocks and Files and WekaIO Matrix Filesystem became the fastest parallel file system in the world to date.

Control, control and control

I studied WekaIO’s architecture prior to this Field Day. And I spent quite a bit of time digesting and understanding their data paths, I/O paths and control paths, in particular, the diagram below:

Starting from the top right corner of the diagram, applications on the Linux client (running Weka Client software) and it presents to the Linux client as a POSIX-compliant file system. Through the network, the Linux client interacts with the WekaIO kernel-based VFS (virtual file system) driver which coordinates the Front End (grey box in upper right corner) to the Linux client. Other client-based protocols such as NFS, SMB, S3 and HDFS are also supported. The Front End then interacts with the NIC (which can be 10/100G Ethernet, Infiniband, and NVMeoF) through SR-IOV (single root IO virtualization), bypassing the Linux kernel for maximum throughput. This is with WekaIO’s own networking stack in user space. Continue reading