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.

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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

VAST Data must be something special

[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]

Vast Data coming out bash!

The delegates of Storage Field Days were always the lucky bunch. We have witnessed several storage technology companies coming out of stealth at these Tech Field Days. The recent ones in memory for me were Excelero and Hammerspace. But to have one where the venerable storage doyen, Mr. Howard Marks, Vast Data new tech evangelist, to introduce the deep dive of Vast Data technology was something special.

For those who knew Howard, he is fiercely independent, very storage technology smart, opinionated and not easily impressed. As a storage technology connoisseur myself, I believe Howard must have seen something special in Vast Data. They must be doing something extremely unique and impressive that someone like Howard could not resist, and made him jump to the vendor side. This sets the tone of my blog.

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The Return of SAN and NAS with AWS?

AWS what?

Amazon Web Services announced Outposts at re:Invent last week. It was not much of a surprise for me because when AWS had their partnership with VMware in 2016, the undercurrents were there to have AWS services come right at the doorsteps of any datacenter. In my mind, AWS has built so far out in the cloud that eventually, the only way to grow is to come back to core of IT services – The Enterprise.

Their intentions were indeed stealthy, but I have been a believer of the IT pendulum. What has swung out to the left or right would eventually come back to the centre again. History has proven that, time and time again.

SAN and NAS coming back?

A friend of mine casually spoke about AWS Outposts announcements. Does that mean SAN and NAS are coming back? I couldn’t hide my excitement hearing the return but … be still, my beating heart!

I am a storage dinosaur now. My era started in the early 90s. SAN and NAS were a big part of my career, but cloud computing has changed and shaped the landscape of on-premises shared storage. SAN and NAS are probably closeted by the younger generation of storage engineers and storage architects, who are more adept to S3 APIs and Infrastructure-as-Code. The nuts and bolts of Fibre Channel, SMB (or CIFS if one still prefers it), and NFS are of lesser prominence, and concepts such as FLOGI, PLOGI, SMB mandatory locking, NFS advisory locking and even iSCSI IQN are probably alien to many of them.

What is Amazon Outposts?

In a nutshell, AWS will be selling servers and infrastructure gear. The AWS-branded hardware, starting from a single server to large racks, will be shipped to a customer’s datacenter or any hosting location, packaged with AWS popular computing and storage services, and optionally, with VMware technology for virtualized computing resources.

Taken from https://aws.amazon.com/outposts/

In a move ala-Azure Stack, Outposts completes the round trip of the IT Pendulum. It has swung to the left; it has swung to the right; it is now back at the centre. AWS is no longer public cloud computing company. They have just become a hybrid cloud computing company. Continue reading

Sexy HPC storage is all the rage

HPC is sexy

There is no denying it. HPC is sexy. HPC Storage is just as sexy.

Looking at the latest buzz from Super Computing Conference 2018 which happened in Dallas 2 weeks ago, the number of storage related vendors participating was staggering. Panasas, Weka.io, Excelero, BeeGFS, are the ones that I know because I got friends posting their highlights. Then there are the perennial vendors like IBM, Dell, HPE, NetApp, Huawei, Supermicro, and so many more. A quick check on the SC18 website showed that there were 391 exhibitors on the floor.

And this is driven by the unrelentless demand for higher and higher performance of computing, and along with it, the demands for faster and faster storage performance. Commercialization of Artificial Intelligence (AI), Deep Learning (DL) and newer applications and workloads together with the traditional HPC workloads are driving these ever increasing requirements. However, most enterprise storage platforms were not designed to meet the demands of these new generation of applications and workloads, as many have been led to believe. Why so?

I had a couple of conversations with a few well known vendors around the topic of HPC Storage. And several responses thrown back were to put Flash and NVMe to solve the high demands of HPC storage performance. In my mind, these responses were too trivial, too irresponsible. So I wanted to write this blog to share my views on HPC storage, and not just about its performance.

The HPC lines are blurring

I picked up this video (below) a few days ago. It was insideHPC Rich Brueckner interview with Dr. Goh Eng Lim, HPE CTO and renowned HPC expert about the convergence of both traditional and commercial HPC applications and workloads.

I liked the conversation in the video because it addressed the 2 different approaches. And I welcomed Dr. Goh’s invitation to the Commercial HPC community to work with the Traditional HPC vendors to help push the envelope towards Exascale SuperComputing.

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The Malaysian Openstack storage conundrum

The Openstack blippings on my radar have ratcheted up this year. I have been asked to put together the IaaS design several times, either with the flavours of RedHat or Ubuntu, and it’s a good thing to see the Openstack interest level going up in the Malaysian IT scene. Coming into its 8th year, Openstack has become a mature platform but in the storage projects of Openstack, my observations tell me that these storage-related projects are not as well known as we speak.

I was one of the speakers at the Openstack Malaysia 8th Summit over a month ago. I started my talk with question – “Can anyone name the 4 Openstack storage projects?“. The response from the floor was “Swift, Cinder, Ceph and … (nobody knew the 4th one)” It took me by surprise when the floor almost univocally agreed that Ceph is one of the Openstack projects but we know that Ceph isn’t one. Ceph? An Openstack storage project?

Besides Swift, Cinder, there is Glance (depending on how you look at it) and the least known .. Manila.

I have also been following on many Openstack Malaysia discussions and discussion groups for a while. That Ceph response showed the lack of awareness and knowledge of the Openstack storage projects among the Malaysian IT crowd, and it was a difficult issue to tackle. The storage conundrum continues to perplex me because many whom I have spoken to seemed to avoid talking about storage and viewing it like a dark art or some voodoo thingy.

I view storage as the cornerstone of the 3 infrastructure pillars  – compute, network and storage – of Openstack or any software-defined infrastructure stack for that matter. So it is important to get an understanding the Openstack storage projects, especially Cinder.

Cinder is the abstraction layer that gives management and control to block storage beneath it. In a nutshell, it allows Openstack VMs and applications consume block storage in a consistent and secure way, regardless of the storage infrastructure or technology beneath it. This is achieved through the cinder-volume service which is a driver most storage vendors integrate with (as shown in the diagram below).

Diagram in slides is from Mirantis found at https://www.slideshare.net/mirantis/openstack-architecture-43160012

Diagram in slides is from Mirantis found at https://www.slideshare.net/mirantis/openstack-architecture-43160012

Cinder-volume together with cinder-api, and cinder-scheduler, form the Block Storage Services for Openstack. There is another service, cinder-backup which integrates with Openstack Swift but in my last check, this service is not as popular as cinder-volume, which is widely supported by many storage vendors with both Fibre Channel and iSCSi implementations, and in a few vendors, with NFS and SMB as well. Continue reading

Storage dinosaurs evolving too

[Preamble: I am a delegate of Storage Field Day 15 from Mar 7-9, 2018. My expenses, travel and accommodation are paid for by GestaltIT, the organizer and I am not obligated to blog or promote the technologies presented at this event. The content of this blog is of my own opinions and views]

I have been called a dinosaur. We storage networking professionals and storage technologists have been called dinosaurs. It wasn’t offensive or anything like that and I knew it was coming because the writing was on the wall, … or is it?

The cloud and the breakneck pace of all the technologies that came along have made us, the storage networking professionals, look like relics. The storage guys have been pigeonholed into a sunset segment of the IT industry. SAN and NAS, according to the non-practitioners, were no longer relevant. And cloud has clout (pun intended) us out of the park.

I don’t see us that way. I see that the Storage Dinosaurs are evolving as well, and our storage foundational knowledge and experience are more relevant that ever. And the greatest assets that we, the storage networking professionals, have is our deep understanding of data.

A little over a year ago, I changed the term Storage in my universe to Data Services Platform, and here was the blog I wrote. I blogged again just before the year 2018 began.

 

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Of Object Storage, Filesystems and Multi-Cloud

Data storage silos everywhere. The early clarion call was to eliminate IT data storage silos by moving to the cloud. Fast forward to the present. Data storage silos are still everywhere, but this time, they are in the clouds. I blogged about this.

Object Storage was all the rage when it first started. AWS, with its S3 (Simple Storage Service) offering, started the cloud storage frenzy. Highly available, globally distributed, simple to access, and fitted superbly into the entire AWS ecosystem. Quickly, a smorgasbord of S3-compatible, S3-like object-based storage emerged. OpenStack Swift, HDS HCP, EMC Atmos, Cleversafe (which became IBM SpectrumScale), Inktank Ceph (which became RedHat Ceph), Bycast (acquired by NetApp to be StorageGrid), Quantum Lattus, Amplidata, and many more. For a period of a few years prior, it looked to me that the popularity of object storage with an S3 compatible front has overtaken distributed file systems.

What’s not to like? Object storage are distributed, they are metadata rich (at a certain structural level), they are immutable (hence secure from a certain point of view), and some even claim self-healing (depending on data protection policies). But one thing that object storage rarely touted dominance was high performance I/O. There were some cases, but they were either fronted by a file system (eg. NFSv4.1 with pNFS extensions), or using some host-based, SAN-client agent (eg. StorNext or Intel Lustre). Object-based storage, in its native form, has not been positioned as high performance I/O storage.

A few weeks ago, I read an article from Storage Soup, Dave Raffo. When I read it, it felt oxymoronic. SwiftStack was just nominated as a visionary in the Gartner Magic Quadrant for Distributed File Systems and Object Storage. But according to Dave’s article, Swiftstack did not want to be “associated” with object storage that much, even though Swiftstack’s technology underpinning was all object storage. Strange.

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Pure Electric!

I didn’t get a chance to attend Pure Accelerate event last month. From the blogs and tweets of my friends, Pure Accelerate was an awesome event. When I got the email invitation for the localized Pure Live! event in Kuala Lumpur, I told myself that I have to attend the event.

The event was yesterday, and I was not disappointed. Coming off a strong fiscal Q1 2018, it has appeared that Pure Storage has gotten many things together, chugging full steam at all fronts.

When Pure Storage first come out, I was one of the early bloggers who took a fancy of them. My 2011 blog mentioned the storage luminaries in their team. Since then, they have come a long way. And it was apt that on the same morning yesterday, the latest Gartner Magic Quadrant for Solid State Arrays 2017 was released.

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